From LANIER.R.A-@smtpgty.bwi.wec.com Mon Apr 01 07:48:52 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id HAA19973 for ; Mon, 1 Apr 1996 07:48:49 -0600 (CST) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA31831; Mon, 1 Apr 1996 08:46:50 -0500 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 15FDEF60; Mon, 1 Apr 96 08:49:42 -0500 Mime-Version: 1.0 Date: Mon, 1 Apr 1996 08:49:31 -0500 Message-Id: <15FDEF60.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:162] FCC APPROVES REALLOCATION PLAN FOR 185 MHz OF S To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part What does this mean for SS useage?? Tony, KE4ATO ______________________________ Reply Separator _________________________________ Subject: [SS:162] FCC APPROVES REALLOCATION PLAN FOR 185 MHz OF SPECT Author: ss@tapr.org at BALT.SMTP Date: 3/29/96 10:50 AM FCC APPROVES REALLOCATION PLAN FOR 185 MHz OF SPECTRUM The FCC has approved a plan to reallocate 185 MHz of spectrum transferred from the Federal Government to the private sector. The Commission also established the scope and timing of future rule-making proceedings to assign the reallocated spectrum. Last March, the Secretary of Commerce identified 235 MHz of Federal Government spectrum for private-sector use, 50 MHz of which had been released earlier. The FCC allocated that spectrum space to general, commercial fixed and mobile uses and unlicensed services. The remaining 185 MHz is to be allocated and assigned gradually over a 10-year period, and a significant portion will be held "in reserve" until that period ends. The Commission says it intends to "consider all options for the appropriate use of the remaining 185 MHz, including, but not limited to, those addressed in allocating the first 50 MHz." Among the services that will be considered is public safety. The Budget Act requires that the FCC study public safety spectrum needs and develop a plan to ensure adequate spectrum through the year 2010. The Public Safety Wireless Advisory Committee--chartered by the FCC and the NTIA--will advise later this year on the operational, technical and spectrum requirements of Federal, state and local public safety entities.--FCC -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dewayne Hendricks, WA8DZP ! CIS: 75210,10 AppleLink: D6547 Warp Speed Imagineering ! Internet: dewayne@warpspeed.com 43730 Vista Del Mar ! Packet Radio: WA8DZP @ K3MC.#NOCAL.CA.USA.NOAM Fremont, CA 94539-3204 ! AOL: HENDRICKS Fax: (510) 770-9854 ! WWW: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ From srbible@mindport.net Mon Apr 08 09:58:56 1996 Received: from polaris.mindport.net (root@polaris.mindport.net [205.219.167.2]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id JAA07966 for ; Mon, 8 Apr 1996 09:58:53 -0500 (CDT) Received: from avatar.greene.net (ppp10.greene.net [206.96.97.110]) by polaris.mindport.net (8.6.12/8.6.12) with SMTP id KAA17017 for ; Mon, 8 Apr 1996 10:58:40 -0400 Posted-Date: Mon, 8 Apr 1996 10:58:40 -0400 Message-Id: <1.5.4b12.32.19960408145853.00695590@mindport.net> X-Sender: srbible@mindport.net X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Mon, 08 Apr 1996 10:58:53 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: League's Comments on SS on Newsline #973 Amateur Radio Newsline April 5th, #973 contains the League's comments on the comments filed on RM-8737, changes to SS rules. You can listen to Newsline from the TAPR web site using RealAudio from the page: http://www.tapr.org/newsline/index.html or you may find the text transcript to read. Give it a listen... 73, - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From LANIER.R.A-@smtpgty.bwi.wec.com Tue Apr 09 15:18:19 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id PAA03271 for ; Tue, 9 Apr 1996 15:18:12 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA08102; Tue, 9 Apr 1996 16:11:13 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16AC5500; Tue, 9 Apr 96 16:15:12 -0400 Mime-Version: 1.0 Date: Tue, 9 Apr 1996 15:18:47 -0400 Message-Id: <16AC5500.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: PN sequencer To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Since little traffic has been moving lately, I thought I would pose a question: When a shift register is used to produce a PN sequence, why is the output of the sequencer inverted? I am specifically refering to the use of an 8-bit shift register (74'164), modulo-2 adding bits 1 and 7, and THEN inverting the result, which then becomes the output of the "system." There was a discussion of this in October 1986 QEX (if anyone has this issue, I would appreciate a copy of the article) and also in the ARRL SS Sourcebook. From looking at other literature on the subject, I can find no mention of the inverter. Was the inverter added as a result of the system it was being used in? I would like to start experimenting with other PN sequences, but this issue needs to be resolved first! 73s de Tony, KE4ATO From jfields@cisco.com Tue Apr 09 17:28:24 1996 Received: from harrier.cisco.com (harrier.cisco.com [171.69.1.173]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id RAA03456 for ; Tue, 9 Apr 1996 17:28:20 -0500 (CDT) Received: (jfields@localhost) by harrier.cisco.com (8.6.8+c/8.6.5) id PAA20750 for ss@tapr.org; Tue, 9 Apr 1996 15:03:59 -0700 Date: Tue, 9 Apr 1996 15:03:59 -0700 From: Julian Fields Message-Id: <199604092203.PAA20750@harrier.cisco.com> To: ss@tapr.org Subject: Re: [SS:165] PN sequencer > When a shift register is used to produce a PN sequence, why is the > output of the sequencer inverted? I am specifically refering to the > use of an 8-bit shift register (74'164), modulo-2 adding bits 1 and 7, > and THEN inverting the result, which then becomes the output of the > "system." Not claiming to be an expert, but a PN sequence inverted is still a PN sequence. So long as both the transmitter and receiver have this inverter, it should work. So, it will work with or without the inverter. Good luck, Julian Fields From LANIER.R.A-@smtpgty.bwi.wec.com Wed Apr 10 07:46:03 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id HAA13114 for ; Wed, 10 Apr 1996 07:45:59 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA28152; Wed, 10 Apr 1996 08:30:31 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16BADCB0; Wed, 10 Apr 96 08:47:07 -0400 Mime-Version: 1.0 Date: Wed, 10 Apr 1996 08:45:50 -0400 Message-Id: <16BADCB0.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:166] Re: PN sequencer To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Julian, I realize that the sequencer will work without the inverter, but why is is there in the first place? Its really not a big deal; I could add one later if needed. Does anyone have access to the QEX article? It is the October 1986 issue. Just curious. 73s de Tony, KE4ATO ______________________________ Reply Separator _________________________________ Subject: [SS:166] Re: PN sequencer Author: ss@tapr.org at BALT.SMTP Date: 4/9/96 5:52 PM > When a shift register is used to produce a PN sequence, why is the > output of the sequencer inverted? I am specifically refering to the > use of an 8-bit shift register (74'164), modulo-2 adding bits 1 and 7, > and THEN inverting the result, which then becomes the output of the > "system." Not claiming to be an expert, but a PN sequence inverted is still a PN sequence. So long as both the transmitter and receiver have this inverter, it should work. So, it will work with or without the inverter. Good luck, Julian Fields From jfields@cisco.com Wed Apr 10 14:56:44 1996 Received: from harrier.cisco.com (harrier.cisco.com [171.69.1.173]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id OAA02600 for ; Wed, 10 Apr 1996 14:56:38 -0500 (CDT) Received: (jfields@localhost) by harrier.cisco.com (8.6.8+c/8.6.5) id MAA27542 for ss@tapr.org; Wed, 10 Apr 1996 12:56:04 -0700 Date: Wed, 10 Apr 1996 12:56:04 -0700 From: Julian Fields Message-Id: <199604101956.MAA27542@harrier.cisco.com> To: ss@tapr.org Subject: Re: [SS:167] Re: PN sequencer It is probably as you suggest (for fanout or gate loading requirements). This brings to mind that you could get 2 pseudo-random sequences from one set of logic without changing taps-- just invert the output. This would get you 2 CMDA channels for the price of one inverter. Maybe somebody at Qualcom can shed more light on your question though. Regards, Julian > > Julian, > > I realize that the sequencer will work without the inverter, but why > is is there in the first place? Its really not a big deal; I could add > one later if needed. > > Does anyone have access to the QEX article? It is the October 1986 > issue. Just curious. > > 73s de > Tony, KE4ATO > > > ______________________________ Reply Separator _________________________________ > Subject: [SS:166] Re: PN sequencer > Author: ss@tapr.org at BALT.SMTP > Date: 4/9/96 5:52 PM > > > > > When a shift register is used to produce a PN sequence, why is the > > output of the sequencer inverted? I am specifically refering to the > > use of an 8-bit shift register (74'164), modulo-2 adding bits 1 and 7, > > and THEN inverting the result, which then becomes the output of the > > "system." > > Not claiming to be an expert, but a PN > sequence inverted is still a PN sequence. So long as both the > transmitter and receiver have this inverter, it should work. > > So, it will work with or without the inverter. > Good luck, > Julian Fields > > > From c-three@telepost.no Wed Apr 10 15:53:27 1996 Received: from netto.telepost.no (netto.telepost.no [193.212.1.11]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id PAA05278 for ; Wed, 10 Apr 1996 15:53:24 -0500 (CDT) Received: from c-three.telepost.no by netto.telepost.no with SMTP (8.6.13/nms1.1) id for ; Wed, 10 Apr 1996 22:53:13 +0200 Message-Id: <199604102053.22144.telepost.no@telepost.no> X-Sender: c-three@telepost.no X-Mailer: Windows Eudora Pro Version 2.1.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Wed, 10 Apr 1996 22:53:14 +0200 To: ss@tapr.org From: Per-Tore Aasestrand Subject: Re: [SS:167] Re: PN sequencer At 08:03 10.04.96 -0500, you wrote: > Julian, > > I realize that the sequencer will work without the inverter, but why > is is there in the first place? Its really not a big deal; I could add > one later if needed. > > Does anyone have access to the QEX article? It is the October 1986 > issue. Just curious. Maybe just in order to increase the drive, or to buffer the signal? Just an idea! Regards, Per-Tore LA7NO ----------------------------------+-------------------------------- | Per-Tore Aasestrand | E-mail : c-three@telepost.no | | C-Three Systems AS | Fax : + 47 - 55 23 18 88 | | P.O. Box 1708 | Voice : + 47 - 55 32 67 67 | | N-5024 Bergen, Norway | Mobile : + 47 - 92 04 44 76 | ----------------------------------+-------------------------------- From c-three@telepost.no Wed Apr 10 15:57:40 1996 Received: from netto.telepost.no (netto.telepost.no [193.212.1.11]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id PAA05396 for ; Wed, 10 Apr 1996 15:57:33 -0500 (CDT) Received: from c-three.telepost.no by netto.telepost.no with SMTP (8.6.13/nms1.1) id for ; Wed, 10 Apr 1996 22:57:27 +0200 Message-Id: <199604102057.22663.telepost.no@telepost.no> X-Sender: c-three@telepost.no X-Mailer: Windows Eudora Pro Version 2.1.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Wed, 10 Apr 1996 22:57:28 +0200 To: ss@tapr.org From: Per-Tore Aasestrand Subject: Re: [SS:168] Re: PN sequencer At 15:10 10.04.96 -0500, you wrote: >It is probably as you suggest (for fanout or gate >loading requirements). This brings to mind that >you could get 2 pseudo-random sequences from >one set of logic without changing taps-- just >invert the output. This would get you 2 CMDA >channels for the price of one inverter. But this will not necessarily be two sequences that are suitable for simultaneous CDMA. The code sequences should be mutually orthogonal, I believe! Regards, Per-Tore LA7NO ----------------------------------+-------------------------------- | Per-Tore Aasestrand | E-mail : c-three@telepost.no | | C-Three Systems AS | Fax : + 47 - 55 23 18 88 | | P.O. Box 1708 | Voice : + 47 - 55 32 67 67 | | N-5024 Bergen, Norway | Mobile : + 47 - 92 04 44 76 | ----------------------------------+-------------------------------- From cbuttsch@slonet.org Wed Apr 10 16:49:10 1996 Received: from biggulp.callamer.com (cbuttsch@biggulp.callamer.com [199.74.141.2]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id QAA08070 for ; Wed, 10 Apr 1996 16:49:05 -0500 (CDT) Received: (from cbuttsch@localhost) by biggulp.callamer.com (8.7.4/8.7.3) id OAA15196; Wed, 10 Apr 1996 14:48:55 -0700 (PDT) Date: Wed, 10 Apr 1996 14:48:55 -0700 (PDT) From: Clifford Buttschardt X-Sender: cbuttsch@biggulp.callamer.com To: "LANIER.R.A-" cc: ss@tapr.org Subject: Re: [SS:167] Re: PN sequencer In-Reply-To: <16BADCB0.1858@smtpgty.bwi.wec.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Hi Julian and Tony. If you guys are in a bind for QEX articles, I suspect I have every one ever published. They are buried in the attic, however and might take some time to find! Cliff Buttschardt W6HDO On Wed, 10 Apr 1996, LANIER.R.A- wrote: > Julian, > > I realize that the sequencer will work without the inverter, but why > is is there in the first place? Its really not a big deal; I could add > one later if needed. > > Does anyone have access to the QEX article? It is the October 1986 > issue. Just curious. > > 73s de > Tony, KE4ATO > > > ______________________________ Reply Separator _________________________________ > Subject: [SS:166] Re: PN sequencer > Author: ss@tapr.org at BALT.SMTP > Date: 4/9/96 5:52 PM > > > > > When a shift register is used to produce a PN sequence, why is the > > output of the sequencer inverted? I am specifically refering to the > > use of an 8-bit shift register (74'164), modulo-2 adding bits 1 and 7, > > and THEN inverting the result, which then becomes the output of the > > "system." > > Not claiming to be an expert, but a PN > sequence inverted is still a PN sequence. So long as both the > transmitter and receiver have this inverter, it should work. > > So, it will work with or without the inverter. > Good luck, > Julian Fields > > > From jfields@cisco.com Wed Apr 10 19:59:07 1996 Received: from harrier.cisco.com (harrier.cisco.com [171.69.1.173]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id TAA16250 for ; Wed, 10 Apr 1996 19:59:04 -0500 (CDT) Received: (jfields@localhost) by harrier.cisco.com (8.6.8+c/8.6.5) id RAA04887; Wed, 10 Apr 1996 17:58:33 -0700 Date: Wed, 10 Apr 1996 17:58:33 -0700 From: Julian Fields Message-Id: <199604110058.RAA04887@harrier.cisco.com> To: ss@tapr.org Subject: Re: [SS:168] Re: PN sequencer Cc: bad@wireless.wdc.net Yes, this could be. By orthogonal, you mean little correlation? Is there a general theorem or do you have to look at each PN code on a case by case basis? Regards, Julian > On Wed, 10 Apr 1996, Julian Fields wrote: > > > It is probably as you suggest (for fanout or gate > > loading requirements). This brings to mind that > > you could get 2 pseudo-random sequences from > > one set of logic without changing taps-- just > > invert the output. This would get you 2 CMDA > > channels for the price of one inverter. > > I tend to disagree. The inverse of a PN code is not generaly orthogonal > to the noninverted PN code. > > Bernie From bad@wireless.wdc.net Wed Apr 10 20:42:39 1996 Received: from wireless.wdc.net (wireless.wdc.net [204.140.136.28]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id UAA18093 for ; Wed, 10 Apr 1996 20:42:37 -0500 (CDT) Received: (from bad@localhost) by wireless.wdc.net (8.6.12/8.6.12) id SAA08080; Mon, 10 Apr 1995 18:44:14 -0700 Date: Mon, 10 Apr 1995 18:44:13 -0700 (PDT) From: Bernie Doehner To: ss@tapr.org Subject: Re: [SS:168] Re: PN sequencer In-Reply-To: <199604110048.RAA04704@harrier.cisco.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII > Yes, this could be. > By orthogonal, you mean little correlation? > Is there a general theorem or do you have > to look at each PN code on a case by case basis? > Regards, > Julian We could take this to formal Probability, but lets start with something simple: Take sin(x), inverted you get -sin(x). sin(x) is NEVER orthogonal to -sin(x). The only way to get orthogonality is with another carrier/signal separated by 90 degrees (Ie. cos(x)). To paraphrase your statement: given any sequence, I can do CDMA, by inverting the sequence. In order to maximize isolation between users, you must use orthogonal codes. Using inverses, may reduce crosscorrelation between certain pairs of PN codes, but is not generaly true. If you quantize "my" sin(x) to 1 bit (sqare wave). The same point still holds (inverse of a square wave is not orthogonal to the original). I have just given you one possible PN codes for which your statement doesn't hold, hence it's not generaly applicable. As far as I know, the only way I know of to get truely orthogonal is through computation, or using the same PN sequence twice, but running the clock of one of these sequences at an integral multiple of the other. In essense frequency division multiplexing the PN codes. Bernie From c-three@telepost.no Thu Apr 11 06:58:52 1996 Received: from netto.telepost.no (netto.telepost.no [193.212.1.11]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id GAA20301 for ; Thu, 11 Apr 1996 06:58:42 -0500 (CDT) Received: from c-three.telepost.no by netto.telepost.no with SMTP (8.6.13/nms1.1) id for ; Thu, 11 Apr 1996 13:57:20 +0200 Message-Id: <199604111157.401.telepost.no@telepost.no> X-Sender: c-three@telepost.no X-Mailer: Windows Eudora Pro Version 2.1.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Thu, 11 Apr 1996 13:57:21 +0200 To: ss@tapr.org From: Per-Tore Aasestrand Subject: Does DSSS actually reduce AWGN ? I have just been reading parts of the book by Dr. Kamilo Feher: "Wireless Digital Communications", P-H 1995. In his introduction to spread-spectrum he writes: "Bandwidth expansion is achieved by a second modulation means, a means that is independent of the information message. For this reason this expansion does not combat additive white Gaussian noise, as does wideband FM." (Later he is elaborating further on this. If you give me your fax number, I can send you a copy of the two pages in question.) This statement has puzzled me quite a bit, maybe because I just don't understand him correctly. But I have always had the impression that this was just what DSSS was able to do - reduce the thermal noise by a factor approximately equeal to the processing gain! This is the fundamental issue for the GPS system, which operates at -30 dB S/N ratio in the receiver front-end! I would very much appreciate your comment on this. 73'es de LA7NO Per-Tore ----------------------------------+-------------------------------- | Per-Tore Aasestrand | E-mail : c-three@telepost.no | | C-Three Systems AS | Fax : + 47 - 55 23 18 88 | | P.O. Box 1708 | Voice : + 47 - 55 32 67 67 | | N-5024 Bergen, Norway | Mobile : + 47 - 92 04 44 76 | ----------------------------------+-------------------------------- From wb9mjn@wb9mjn.ampr.org Thu Apr 11 08:01:27 1996 Received: from wb9mjn.ampr.org (wb9mjn.ampr.org [44.72.98.19]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id IAA22078 for ; Thu, 11 Apr 1996 08:01:15 -0500 (CDT) From: wb9mjn@wb9mjn.ampr.org Date: Thu, 11 Apr 96 07:13:27 UTC Message-Id: <9660@wb9mjn.ampr.org> To: ss@tapr.org Subject: Re: [SS:174] Does DSSS actually reduce AWGN ? In-Reply-To: your message of Thu Apr 11 07:04:41 1996 <199604111157.401.telepost.no@telepost.no> Hi Per-Tore, I believe Dr. Feher is means that there is no noise benefit from the spreading-despreading process. Its a trade off. When u spread, the signal goes down to the noise level (at the reciever), but when u despread in the reciever, the S/N ratio of the resulting signal, is the same as if the transmission had been made by that resulting signal, without the spreading and despreading. With FM, however, above the threshold effect, the widening of the signal results in an improvement of demodulated S/N ratio above and beyond the RF S/N ratio by a factor of 3/2 Beta-squared. Where Beta is the modulation index, which is the deviation / Maximun modulation Frequency. With the DSSS spreading and despreading there is no gain of S/N by widening the signal. The output S/N ratio is the same as the input S/N ratio. With FM, tho, there is (above the threshold effect). The biggest advantage of DSSS is the ability reduce the effects of delay spread. Above 1 Ghz, these are a make-break problem in mobile communications. I was particularily impressed by this, when N9HSI demonstrated the use of a 1.2 Ghz 40 watt repeater to me on lunch break, one day. When we drove thru an intersection, the receiver wildely was driven between squelched and full scale. It seems that every street light, at the range we were at, was acting like a reflecting periscope antenna. And all these antennas did not neccasarily sum in phase, as we drove along. WBFM would not be able to combat this problem at all. While, DSSS with a RAKE receiver can. 73, Don. WB9MJN. 73, Don. Mailbox : WB9MJN @ N9HSI.IL.USA.NA AMPRNet : wb9mjn@wb9mjn.ampr.org[44.72.98.19] Internet: wb9mjn%wb9mjn.ampr.org@uugate.aim.utah.edu From djk@chbi.co.uk Thu Apr 11 08:30:25 1996 Received: from dns.chbi.co.uk (root@dns.chbi.co.uk [194.72.251.2]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id IAA23084 for ; Thu, 11 Apr 1996 08:30:16 -0500 (CDT) Received: from dns.leather.chbi.co.uk (dns.leather.chbi.co.uk [192.168.0.3]) by dns.chbi.co.uk (8.7.1/8.7.1) with ESMTP id NAA24955 for ; Thu, 11 Apr 1996 13:30:14 +0100 Received: (from djk@localhost) by dns.leather.chbi.co.uk (8.7.1/8.7.1) id NAA11677; Thu, 11 Apr 1996 13:33:22 +0100 Date: Thu, 11 Apr 1996 13:33:21 +0100 (BST) From: Dirk-Jan Koopman X-Sender: djk@dns.leather.chbi.co.uk To: ss@tapr.org Subject: DS (or anything) key management Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII In the UK, SS is technically illegal (well actually it isn't, but our licencing authorities will say it is if anybody uses it, so it is :-). The good news is that they seriously wish to make it legal, but they have a fundemental problem which needs to be overcome (and is the reason that they say it is illegal) and that is DS key publication. We need to find a mechanism which allows any suitably equiped amateur to be able to decode any licenced SS conversation. This is the only (real) stumbling block to legalising SS in the UK. Has anyone got any thoughts as to how it might be possible to have many SS conversations going on using different keys and being able to resolve any one of them. Is there an algorithm which generates suitably pseudo random keys based on some ID value such as frequency or callsign (or pseudo callsign identifying a 'net')? We have a requirement here in the UK for CWid every 30 minutes anyway which could be used to ID a seed value to the key generator. Any thoughts? Dirk From LANIER.R.A-@smtpgty.bwi.wec.com Thu Apr 11 09:20:28 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id JAA25710 for ; Thu, 11 Apr 1996 09:20:26 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA04598; Thu, 11 Apr 1996 09:51:06 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16D15250; Thu, 11 Apr 96 10:20:21 -0400 Mime-Version: 1.0 Date: Thu, 11 Apr 1996 10:21:05 -0400 Message-Id: <16D15250.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:173] Re: PN sequencer To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part You could THEORETICALLY achieve orthogonality using codes that are the exact opposite of each other. I say this only from the brief material that I have read on the subject. I haven't studied, in detail, this aspect os SS yet, so don't clobber me :) Orthogonality would only come into play if there are two adjacent SS receivers. A way to alleviate this situation could be to have an "address" for each receiver or a specific sych code sent every few seconds. Or possibly use one PN sequence to clock another PN sequence. Just a few thoughts... 73s de Tony, KE4ATO ______________________________ Reply Separator _________________________________ Subject: [SS:173] Re: PN sequencer Author: ss@tapr.org at BALT.SMTP Date: 4/10/96 8:50 PM > Yes, this could be. > By orthogonal, you mean little correlation? > Is there a general theorem or do you have > to look at each PN code on a case by case basis? > Regards, > Julian We could take this to formal Probability, but lets start with something simple: Take sin(x), inverted you get -sin(x). sin(x) is NEVER orthogonal to -sin(x). The only way to get orthogonality is with another carrier/signal separated by 90 degrees (Ie. cos(x)). To paraphrase your statement: given any sequence, I can do CDMA, by inverting the sequence. In order to maximize isolation between users, you must use orthogonal codes. Using inverses, may reduce crosscorrelation between certain pairs of PN codes, but is not generaly true. If you quantize "my" sin(x) to 1 bit (sqare wave). The same point still holds (inverse of a square wave is not orthogonal to the original). I have just given you one possible PN codes for which your statement doesn't hold, hence it's not generaly applicable. As far as I know, the only way I know of to get truely orthogonal is through computation, or using the same PN sequence twice, but running the clock of one of these sequences at an integral multiple of the other. In essense frequency division multiplexing the PN codes. Bernie From LANIER.R.A-@smtpgty.bwi.wec.com Thu Apr 11 09:26:16 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id JAA25813 for ; Thu, 11 Apr 1996 09:26:13 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA27265; Thu, 11 Apr 1996 09:57:15 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16D16D10; Thu, 11 Apr 96 10:27:29 -0400 Mime-Version: 1.0 Date: Thu, 11 Apr 1996 10:29:01 -0400 Message-Id: <16D16D10.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:174] Does DSSS actually reduce AWGN ? To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Hi Per-Tore, Maybe what he means is spreading of the signal does not alleviate noise from the system and he was just giving an example. I can give you his e-mail address and you can ask him yourself. By the way, how do you like the book? I have thought of buying the book myself. Robert Buaas knows him personally and says he is a very smart man. 73s de Tony, KE4ATO ______________________________ Reply Separator _________________________________ Subject: [SS:174] Does DSSS actually reduce AWGN ? Author: ss@tapr.org at BALT.SMTP Date: 4/11/96 7:04 AM I have just been reading parts of the book by Dr. Kamilo Feher: "Wireless Digital Communications", P-H 1995. In his introduction to spread-spectrum he writes: "Bandwidth expansion is achieved by a second modulation means, a means that is independent of the information message. For this reason this expansion does not combat additive white Gaussian noise, as does wideband FM." (Later he is elaborating further on this. If you give me your fax number, I can send you a copy of the two pages in question.) This statement has puzzled me quite a bit, maybe because I just don't understand him correctly. But I have always had the impression that this was just what DSSS was able to do - reduce the thermal noise by a factor approximately equeal to the processing gain! This is the fundamental issue for the GPS system, which operates at -30 dB S/N ratio in the receiver front-end! I would very much appreciate your comment on this. 73'es de LA7NO Per-Tore ----------------------------------+-------------------------------- | Per-Tore Aasestrand | E-mail : c-three@telepost.no | | C-Three Systems AS | Fax : + 47 - 55 23 18 88 | | P.O. Box 1708 | Voice : + 47 - 55 32 67 67 | | N-5024 Bergen, Norway | Mobile : + 47 - 92 04 44 76 | ----------------------------------+-------------------------------- From bad@wireless.wdc.net Thu Apr 11 09:35:48 1996 Received: from wireless.wdc.net (wireless.wdc.net [204.140.136.28]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id JAA26425 for ; Thu, 11 Apr 1996 09:35:45 -0500 (CDT) Received: (from bad@localhost) by wireless.wdc.net (8.6.12/8.6.12) id HAA02202; Thu, 11 Apr 1996 07:34:54 -0700 Date: Thu, 11 Apr 1996 07:34:53 -0700 (PDT) From: Bernie Doehner To: ss@tapr.org Subject: Re: [SS:174] Does DSSS actually reduce AWGN ? In-Reply-To: <199604111157.401.telepost.no@telepost.no> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII On Thu, 11 Apr 1996, Per-Tore Aasestrand wrote: > I have just been reading parts of the book by Dr. Kamilo Feher: "Wireless > Digital Communications", P-H 1995. In his introduction to spread-spectrum he > writes: > > "Bandwidth expansion is achieved by a second modulation means, a means that > is independent of the information message. For this reason this expansion > does not combat additive white Gaussian noise, as does wideband FM." > > (Later he is elaborating further on this. If you give me your fax number, I > can send you a copy of the two pages in question.) > > This statement has puzzled me quite a bit, maybe because I just don't > understand him correctly. But I have always had the impression that this was > just what DSSS was able to do - reduce the thermal noise by a factor > approximately equeal to the processing gain! This is the fundamental issue > for the GPS system, which operates at -30 dB S/N ratio in the receiver > front-end! > > I would very much appreciate your comment on this. > This statement also puzzles me. Just the other day, I saw a short description in Dixon's book, that mentions the exact same thing (GPS operating at -30dB S/N) (I can dig it out later). Is it possible that Dr. Feher's bandwidth, when measuring the noise floor is different then Dixon's? Bernie From ATVQ@aol.com Thu Apr 11 09:53:29 1996 Received: from emout07.mail.aol.com (emout07.mx.aol.com [198.81.11.22]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id JAA27394 for ; Thu, 11 Apr 1996 09:53:25 -0500 (CDT) From: ATVQ@aol.com Received: by emout07.mail.aol.com (8.6.12/8.6.12) id KAA18603 for ss@tapr.org; Thu, 11 Apr 1996 10:52:47 -0400 Date: Thu, 11 Apr 1996 10:52:47 -0400 Message-ID: <960411105246_373417196@emout07.mail.aol.com> To: ss@tapr.org Subject: Re: [SS:175] Re: Does DSSS actually reduce AWGN ? I have not experienceed that effect at 1.2 ghz (lamp post multipath) I have had a similar experience with parallel walls of buildings while driving forming a "wave guide" with cancellation/reinforcement fields, but the wavelength was so short, and the speed high enough it was not perceptabel on the meter, only as a warble inthe audio. In the LA aea I find 1.2 range nearly equal to 2 meters. 73 Henry KB9FO. From jra1854@tntech.edu Thu Apr 11 10:15:15 1996 Received: from tntech.edu (SYSTEM@gemini.tntech.edu [149.149.11.7]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id KAA28583 for ; Thu, 11 Apr 1996 10:15:09 -0500 (CDT) Received: from [149.149.42.11] ("port 1938"@cookie-monster.ece.tntech.edu) by tntech.edu (PMDF V5.0-5 #11446) id <01I3EU16BFCWQS2F1P@tntech.edu> for ss@tapr.org; Thu, 11 Apr 1996 10:14:31 -0500 (CDT) Date: Thu, 11 Apr 1996 10:14:30 -0600 From: jra1854@tntech.edu (Jeffrey Austen) Subject: Re: Does DSSS actually reduce AWGN ? X-Sender: jra1854@gemini.tntech.edu To: ss@tapr.org Message-id: MIME-version: 1.0 Content-type: text/plain; charset="us-ascii" Content-transfer-encoding: 7BIT >I have just been reading parts of the book by Dr. Kamilo Feher: "Wireless >Digital Communications", P-H 1995. In his introduction to spread-spectrum he >writes: > >"Bandwidth expansion is achieved by a second modulation means, a means that >is independent of the information message. For this reason this expansion >does not combat additive white Gaussian noise, as does wideband FM." > >(Later he is elaborating further on this. If you give me your fax number, I >can send you a copy of the two pages in question.) > >This statement has puzzled me quite a bit, maybe because I just don't >understand him correctly. But I have always had the impression that this was >just what DSSS was able to do - reduce the thermal noise by a factor >approximately equeal to the processing gain! This is the fundamental issue >for the GPS system, which operates at -30 dB S/N ratio in the receiver >front-end! The statement is correct: no form of SS will reduce the level of white noise. This can be explained by analyzing the bandwidth at different points in a DSSS system. The signal power is constant whether spread or not. The noise power, however, depends on bandwidth because white noise has a constant power per unit frequency. If the signal bandwidth is increased by a factor of K when spreading the signal, the power remains the same; however, the noise power within the signal bandwidth, which is now K times as large, increases by a factor of K. When the signal is despread the inverse happens: the signal power again remains the same but the noise power decreases by a factor of K because the bandwidth has decreased. (White noise, when despread, is still white noise and has the same power per unit frequency as it did before the despreading operation.) As an example, PANSAT uses BPSK DSSS with a chip rate of 1.25 Mc/s and a chip-to-bit ratio of 127 which provides a processing gain of 21 dB. Before despreading the signal bandwidth is approximately 2.5 MHz and after despreading it is approximately 19.7 kHz. That is a ratio of 127. The noise power in the 2.5 MHz bandwidth will be 127 (21 dB) times as large as the noise power in the 19.7 kHz bandwidth. That's where the "processing gain" lies. Jeff, k9ja --- Jeffrey Austen | Tennessee Technological University jra1854@tntech.edu | Box 5004 +1 615 372 3485 | Cookeville Tennessee 38505 U.S.A. From Robert.Glassey@nmp.nokia.com Thu Apr 11 10:22:20 1996 Received: from noknic.nokia.com (noknic.nokia.com [131.228.6.10]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id KAA29088 for ; Thu, 11 Apr 1996 10:22:15 -0500 (CDT) From: Robert.Glassey@nmp.nokia.com Received: from samail01.nmp.nokia.com (samail01.nmp.nokia.com [131.228.240.6]) by noknic.nokia.com (8.6.9/8.6.9) with ESMTP id SAA21662 for ; Thu, 11 Apr 1996 18:21:09 +0300 Received: from by samail01.nmp.nokia.com with SMTP (1.37.109.16/16.2) id AA254845743; Thu, 11 Apr 1996 18:15:43 +0300 X-Openmail-Hops: 2 Date: Thu, 11 Apr 96 16:19:21 +0100 Message-Id: In-Reply-To: <16AC5500.1858@smtpgty.bwi.wec.com> Subject: [SS:165] PN sequencer Sender: Robert.Glassey@nmp.nokia.com To: ss@tapr.org > When a shift register is used to produce a PN sequence, why is the > output of the sequencer inverted? I am specifically refering to the > use of an 8-bit shift register (74'164), modulo-2 adding bits 1 and 7, > and THEN inverting the result, which then becomes the output of the > "system." There was a discussion of this in October 1986 QEX (if > anyone has this issue, I would appreciate a copy of the article) and > also in the ARRL SS Sourcebook. If I recall correctly, this was to prevent a lockout condition where the shift register contains all zeros. In this case the mod-2 addition of any generator polynomial will result in 0, thus in the next cycle the shift register will still be all zeros. The inverter overcomes this problem, allowing the PN sequence generator to start from the all clear condition, ie reset. I think there are still some other lockout states, like all 1's or 101010.. etc but they will depend upon the polynomial you use. Cheers, Rob From LANIER.R.A-@smtpgty.bwi.wec.com Thu Apr 11 11:23:14 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id LAA02205 for ; Thu, 11 Apr 1996 11:23:11 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA21778; Thu, 11 Apr 1996 11:52:52 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16D31FA0; Thu, 11 Apr 96 12:23:22 -0400 Mime-Version: 1.0 Date: Thu, 11 Apr 1996 12:06:04 -0400 Message-Id: <16D31FA0.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:176] DS (or anything) key management To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Dirk, One method you could use would be to limit the Pn sequences amateurs use. Here in the states we are allowed only three, but I hope that will change in the future :) . There are many such ways this can be implemented, but the most successful will be the easiest. SS is difficult enough without adding some esoteric descrambling algothrim into the mix! Another possible idea is to give each user a unique address and with that address a particular PN sequence picked from a general "database" of PN sequences. This could be used in a net-like atmosphere, where only individuals of a given net have a particular PN sequence. For example, addresses 000-099 could use PN sequence [7,1], addresses 100-199 could use PN sequence [13,4,3,1] and so on. 73s de Tony, KE4ATO ______________________________ Reply Separator _________________________________ Subject: [SS:176] DS (or anything) key management Author: ss@tapr.org at BALT.SMTP Date: 4/11/96 8:42 AM In the UK, SS is technically illegal (well actually it isn't, but our licencing authorities will say it is if anybody uses it, so it is :-). The good news is that they seriously wish to make it legal, but they have a fundemental problem which needs to be overcome (and is the reason that they say it is illegal) and that is DS key publication. We need to find a mechanism which allows any suitably equiped amateur to be able to decode any licenced SS conversation. This is the only (real) stumbling block to legalising SS in the UK. Has anyone got any thoughts as to how it might be possible to have many SS conversations going on using different keys and being able to resolve any one of them. Is there an algorithm which generates suitably pseudo random keys based on some ID value such as frequency or callsign (or pseudo callsign identifying a 'net')? We have a requirement here in the UK for CWid every 30 minutes anyway which could be used to ID a seed value to the key generator. Any thoughts? Dirk From jfields@cisco.com Thu Apr 11 12:15:52 1996 Received: from harrier.cisco.com (harrier.cisco.com [171.69.1.173]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id MAA04664 for ; Thu, 11 Apr 1996 12:15:50 -0500 (CDT) Received: (jfields@localhost) by harrier.cisco.com (8.6.8+c/8.6.5) id KAA00989 for ss@tapr.org; Thu, 11 Apr 1996 10:15:18 -0700 Date: Thu, 11 Apr 1996 10:15:18 -0700 From: Julian Fields Message-Id: <199604111715.KAA00989@harrier.cisco.com> To: ss@tapr.org Subject: Re: [SS:178] Re: Does DSSS actually reduce AWGN ? > Hi Per-Tore, > > Maybe what he means is spreading of the signal does not alleviate > noise from the system and he was just giving an example. I can give > you his e-mail address and you can ask him yourself. > > By the way, how do you like the book? I have thought of buying the > book myself. Robert Buaas knows him personally and says he is a very > smart man. > > 73s de > Tony, KE4ATO Hi Tony, I have just recently bought the book. It is mostly theory written at a level for a 4th year class you would take in university or maybe even masters level. It is one of the top books out there on this subject. Certainly Dr. Kamilo Feher knows his subject well!! The only minor problem is that the book keeps refering to other papers that I don't have access to, so I had to buy a second book to fill in a few areas I had questions about. Regards Julian From LANIER.R.A-@smtpgty.bwi.wec.com Thu Apr 11 12:41:45 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id MAA06034 for ; Thu, 11 Apr 1996 12:41:29 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA28766; Thu, 11 Apr 1996 13:10:24 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16D44750; Thu, 11 Apr 96 13:42:13 -0400 Mime-Version: 1.0 Date: Thu, 11 Apr 1996 13:42:27 -0400 Message-Id: <16D44750.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:181] Re: Does DSSS actually reduce AWGN ? To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Jeff, I would like to know your references for the discussion below. I would like to know more... Also, aren't your involved in a receiver project for the PANSAT satellite? How is that coming along? 73s de Tony, KE4ATO ______________________________ Reply Separator _________________________________ Subject: [SS:181] Re: Does DSSS actually reduce AWGN ? Author: ss@tapr.org at BALT.SMTP Date: 4/11/96 10:35 AM >I have just been reading parts of the book by Dr. Kamilo Feher: "Wireless >Digital Communications", P-H 1995. In his introduction to spread-spectrum he >writes: > >"Bandwidth expansion is achieved by a second modulation means, a means that >is independent of the information message. For this reason this expansion >does not combat additive white Gaussian noise, as does wideband FM." > >(Later he is elaborating further on this. If you give me your fax number, I >can send you a copy of the two pages in question.) > >This statement has puzzled me quite a bit, maybe because I just don't >understand him correctly. But I have always had the impression that this was >just what DSSS was able to do - reduce the thermal noise by a factor >approximately equeal to the processing gain! This is the fundamental issue >for the GPS system, which operates at -30 dB S/N ratio in the receiver >front-end! The statement is correct: no form of SS will reduce the level of white noise. This can be explained by analyzing the bandwidth at different points in a DSSS system. The signal power is constant whether spread or not. The noise power, however, depends on bandwidth because white noise has a constant power per unit frequency. If the signal bandwidth is increased by a factor of K when spreading the signal, the power remains the same; however, the noise power within the signal bandwidth, which is now K times as large, increases by a factor of K. When the signal is despread the inverse happens: the signal power again remains the same but the noise power decreases by a factor of K because the bandwidth has decreased. (White noise, when despread, is still white noise and has the same power per unit frequency as it did before the despreading operation.) As an example, PANSAT uses BPSK DSSS with a chip rate of 1.25 Mc/s and a chip-to-bit ratio of 127 which provides a processing gain of 21 dB. Before despreading the signal bandwidth is approximately 2.5 MHz and after despreading it is approximately 19.7 kHz. That is a ratio of 127. The noise power in the 2.5 MHz bandwidth will be 127 (21 dB) times as large as the noise power in the 19.7 kHz bandwidth. That's where the "processing gain" lies. Jeff, k9ja --- Jeffrey Austen | Tennessee Technological University jra1854@tntech.edu | Box 5004 +1 615 372 3485 | Cookeville Tennessee 38505 U.S.A. From jra1854@tntech.edu Thu Apr 11 13:27:50 1996 Received: from tntech.edu (SYSTEM@gemini.tntech.edu [149.149.11.7]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id NAA08247 for ; Thu, 11 Apr 1996 13:27:47 -0500 (CDT) Received: from [149.149.42.11] ("port 1585"@cookie-monster.ece.tntech.edu) by tntech.edu (PMDF V5.0-5 #11446) id <01I3F0NRLRW0QS3K6S@tntech.edu> for ss@tapr.org; Thu, 11 Apr 1996 13:24:33 -0500 (CDT) Date: Thu, 11 Apr 1996 13:24:32 -0600 From: jra1854@tntech.edu (Jeffrey Austen) Subject: Re: PN sequencer X-Sender: jra1854@gemini.tntech.edu To: ss@tapr.org Message-id: MIME-version: 1.0 Content-type: text/plain; charset="us-ascii" Content-transfer-encoding: 7BIT >> When a shift register is used to produce a PN sequence, why is the >> output of the sequencer inverted? I am specifically refering to the >> use of an 8-bit shift register (74'164), modulo-2 adding bits 1 and 7, >> and THEN inverting the result, which then becomes the output of the >> "system." There was a discussion of this in October 1986 QEX (if >> anyone has this issue, I would appreciate a copy of the article) and >> also in the ARRL SS Sourcebook. > >If I recall correctly, this was to prevent a lockout condition where the >shift register contains all zeros. In this case the mod-2 addition of >any generator polynomial will result in 0, thus in the next cycle the >shift register will still be all zeros. > >The inverter overcomes this problem, allowing the PN sequence generator >to start from the all clear condition, ie reset. > >I think there are still some other lockout states, like all 1's or >101010.. etc but they will depend upon the polynomial you use. The previous notes did not make clear that the inverter is in the feedback loop as well as being the point where the output is taken. If the output of this circuit is inverted the result is identical to the output of the circuit without the inverter. The "lockout" state is now all 1s instead of all 0s; in this state the output would be a continuous stream of 1s. Because the '164 has a clear input but does not have a preset input the circuit with the inverter is more practical since this one state can be avoided. The circuit shown in the Spread Spectrum Sourcebook (chapter 8, page 5) does not take advantage of this; an RC circuit to force the /clear input active would insure proper startup when power is applied -- add a capacitor from pin 9 to ground. Jeff, k9ja --- Jeffrey Austen | Tennessee Technological University jra1854@tntech.edu | Box 5004 +1 615 372 3485 | Cookeville Tennessee 38505 U.S.A. From LANIER.R.A-@smtpgty.bwi.wec.com Thu Apr 11 17:05:30 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id RAA20336 for ; Thu, 11 Apr 1996 17:05:28 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA19059; Thu, 11 Apr 1996 17:31:59 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16D81E20; Thu, 11 Apr 96 18:04:18 -0400 Mime-Version: 1.0 Date: Thu, 11 Apr 1996 18:03:05 -0400 Message-Id: <16D81E20.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:186] Re: PN sequencer To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part This same type of thing can be also be accomplished inside a PLD. The Atmel ATV750 has a power-on reset state, so the device is reset automatically when power is applied. A really nice part. And they're cheap too :) But you need the right programmer :( I received a note from Bob Buaas on this subject. The inverter is needed to fullfill the PN sequence equation: x^7 + x + 1. The +1 part is the inverter; otherwise the sequence would converge after 127 clock pulses. I'll will into this matter some more... 73s de Tony, KE4ATO ______________________________ Reply Separator _________________________________ Subject: [SS:186] Re: PN sequencer Author: ss@tapr.org at BALT.SMTP Date: 4/11/96 1:35 PM >> When a shift register is used to produce a PN sequence, why is the >> output of the sequencer inverted? I am specifically refering to the >> use of an 8-bit shift register (74'164), modulo-2 adding bits 1 and 7, >> and THEN inverting the result, which then becomes the output of the >> "system." There was a discussion of this in October 1986 QEX (if >> anyone has this issue, I would appreciate a copy of the article) and >> also in the ARRL SS Sourcebook. > >If I recall correctly, this was to prevent a lockout condition where the >shift register contains all zeros. In this case the mod-2 addition of >any generator polynomial will result in 0, thus in the next cycle the >shift register will still be all zeros. > >The inverter overcomes this problem, allowing the PN sequence generator >to start from the all clear condition, ie reset. > >I think there are still some other lockout states, like all 1's or >101010.. etc but they will depend upon the polynomial you use. The previous notes did not make clear that the inverter is in the feedback loop as well as being the point where the output is taken. If the output of this circuit is inverted the result is identical to the output of the circuit without the inverter. The "lockout" state is now all 1s instead of all 0s; in this state the output would be a continuous stream of 1s. Because the '164 has a clear input but does not have a preset input the circuit with the inverter is more practical since this one state can be avoided. The circuit shown in the Spread Spectrum Sourcebook (chapter 8, page 5) does not take advantage of this; an RC circuit to force the /clear input active would insure proper startup when power is applied -- add a capacitor from pin 9 to ground. Jeff, k9ja --- Jeffrey Austen | Tennessee Technological University jra1854@tntech.edu | Box 5004 +1 615 372 3485 | Cookeville Tennessee 38505 U.S.A. From n7hpr@tapr.org Fri Apr 12 07:57:14 1996 Received: from polaris.mindport.net (root@polaris.mindport.net [205.219.167.2]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id HAA03815 for ; Fri, 12 Apr 1996 07:57:11 -0500 (CDT) Received: from avatar.greene.net (ppp18.greene.net [206.96.97.118]) by polaris.mindport.net (8.6.12/8.6.12) with SMTP id IAA09913 for ; Fri, 12 Apr 1996 08:57:08 -0400 Posted-Date: Fri, 12 Apr 1996 08:57:08 -0400 Message-Id: <1.5.4b12.32.19960412125709.0068d150@mindport.net> X-Sender: srbible@mindport.net X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 12 Apr 1996 08:57:09 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: Stanford Telecom web pages Stanford Telecom finally has web pages. They have a branch that manufactures SS ASIC chips. I have a product brocure that is a couple of years old. I've been keeping my eye on them for possible ASIC's we could use for a SS modem design. The web pages are not complete. The home page URL is http://www.stel.com Here's a sample from the Wireless & Cable Products Group (WCP) page: ASICs WCP's wide range of ASICs for digital communications is the basis for its range of standard and custom products. This rapidly-expanding group of products provides solutions for a variety of sophisticated communications functions in today's complex environment. WCP's ASIC products include devices designed for: Demodulation Spread Spectrum Forward Error Correction Coding Decoding Direct Digital Synthesis (DDS) WCP offers custom design services for special requirements. The Custom Products group is staffed with experts in custom and semi-custom IC design as well as system and application engineers to provide in-depth design support to a wide range of customers. Devices are available in mil spec and radiation-hardened versions as well as commercial packaging. - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From n7hpr@tapr.org Fri Apr 12 07:57:27 1996 Received: from polaris.mindport.net (root@polaris.mindport.net [205.219.167.2]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id HAA03833 for ; Fri, 12 Apr 1996 07:57:25 -0500 (CDT) Received: from avatar.greene.net (ppp18.greene.net [206.96.97.118]) by polaris.mindport.net (8.6.12/8.6.12) with SMTP id IAA09926 for ; Fri, 12 Apr 1996 08:57:21 -0400 Posted-Date: Fri, 12 Apr 1996 08:57:21 -0400 Message-Id: <1.5.4b12.32.19960412125722.0069687c@mindport.net> X-Sender: srbible@mindport.net X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 12 Apr 1996 08:57:22 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: Stanford Telelcom part 2 from the Wireless & Cable Products Group (WCP) page: Wireless Communications Spread spectrum wireless communications, once the exclusive purview of the military, has come into its own with applications ranging from CDMA phones, cordless PBX systems, vehicle positioning, and wireless LANS. A spread spectrum system transmits both voice and data by spreading signals throughout the radio spectrum, often by employing direct-sequence modulation. Direct-sequence modulation (WCP's preferred method) transmits a high bit-rate pseudo-random code interspersed with the data signals over a broad bandwidth. This produces a highly efficient output that is much more difficult to decipher than linear, single-frequency transmissions. The receiving end efficiently recombines the dispersed and differentially transmitted signals, reproducing the original analog signal. Spread spectrum provides a secure transmission that is highly noise-resistant. A 1995 focus group study conducted by IDC, "Small Business and 13 Corporation Wireless Data Applications and Services, showed that, though only 4.5% of the participants had already installed wireless LANS, 52.5% were in the evaluation process or about to implement Wireless LANs in their corporations. WCP is providing wireless LAN architectures currently being adopted in Europe by ETSI. Stanford Telecom has been a leader in spread spectrum since its inception. The company's founders were instrumental in developing the fundamental waveforms for this technology. Today, WCP provides products for wireless local loop CDMA telephony, like "Airspan," a wireless telephone system developed by DSC Communications that is used by British Telephone and International TelCell, among others. Stanford Telecom's CDMA architecture is based on a patented orthogonal CDMA technology that greatly reduces the effect of signal multipath interference. In vehicle tracking and positioning, WCP spread spectrum products are being used in applications including tracking police cars and taxis, providing GPS/cellular vehicle assistance service, and other vehicle positioning systems. Spread Spectrum Wireless Communications Products STEL-2000A: This fast acquisition, wireless burst processor provides IF to TX/RX data on a single chip. It automatically tracks the carrier and processes data at rates up to 2.048 Mbps. - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From n7hpr@tapr.org Fri Apr 12 07:58:56 1996 Received: from polaris.mindport.net (root@polaris.mindport.net [205.219.167.2]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id HAA03899 for ; Fri, 12 Apr 1996 07:58:55 -0500 (CDT) Received: from avatar.greene.net (ppp18.greene.net [206.96.97.118]) by polaris.mindport.net (8.6.12/8.6.12) with SMTP id IAA09974 for ; Fri, 12 Apr 1996 08:58:51 -0400 Posted-Date: Fri, 12 Apr 1996 08:58:51 -0400 Message-Id: <1.5.4b12.32.19960412125853.0069cafc@mindport.net> X-Sender: srbible@mindport.net X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 12 Apr 1996 08:58:53 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: SS Books - Must haves Here are are three SS books I recommend. All three are must haves: "THE" Reference Book (revised from a previous 3 vol set): Spread Spectrum Communications Handbook, Revised Edition by Marvin K. Simon, Jim K. Omura, Robert A. Scholtz, and Barry K. Levitt McGraw-Hill, 1994 ISBN: 0-07-057629-7 Price: US$ 99.50 Excellent text, theory and mathematical: Introduction to Spread Spectrum Communications, 1/e by Rodger L. Peterson, Rodger E. Ziemer, and David E. Borth Prentice Hall, 1995 ISBN: 0-201-431623-7 Price: US$ 82.00 Practically oriented, Dixon is a "father" (of sorts) of civilian SS: Spread Spectrum Systems with Commercial Applications, 3rd Ed. by Robert C. Dixon John Wiley & Sons, 1994 ISBN: 0-471-59342-7 Price: US$ 79.95 - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From n7hpr@tapr.org Fri Apr 12 07:59:34 1996 Received: from polaris.mindport.net (root@polaris.mindport.net [205.219.167.2]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id HAA03991 for ; Fri, 12 Apr 1996 07:59:32 -0500 (CDT) Received: from avatar.greene.net (ppp18.greene.net [206.96.97.118]) by polaris.mindport.net (8.6.12/8.6.12) with SMTP id IAA10021 for ; Fri, 12 Apr 1996 08:59:29 -0400 Posted-Date: Fri, 12 Apr 1996 08:59:29 -0400 Message-Id: <1.5.4b12.32.19960412125930.0069220c@mindport.net> X-Sender: srbible@mindport.net X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 12 Apr 1996 08:59:30 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: Possible SS modem >From Randy's SSS online mag... Digital Wireless Corporation, Norcross, GA recently announced its new WIT2400 SS OEM frequency hopping transceiver with "12 dB More Receive Sensitivity" (more than a "wet Noodle?"). They also have the WIT915 with a full one Watt output power available. For more information, contact them at TEL: +1 770-564-5540 or FAX: +1 770-564-5541 -- I really think they have a pretty good product! I'll phone them for a quote. Any thoughts from the group? - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From djk@chbi.co.uk Fri Apr 12 09:22:25 1996 Received: from dns.chbi.co.uk (root@dns.chbi.co.uk [194.72.251.2]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id JAA08311 for ; Fri, 12 Apr 1996 09:22:11 -0500 (CDT) Received: from dns.leather.chbi.co.uk (dns.leather.chbi.co.uk [192.168.0.3]) by dns.chbi.co.uk (8.7.1/8.7.1) with ESMTP id OAA28481 for ; Fri, 12 Apr 1996 14:22:08 +0100 Received: (from djk@localhost) by dns.leather.chbi.co.uk (8.7.1/8.7.1) id OAA15696; Fri, 12 Apr 1996 14:25:26 +0100 Date: Fri, 12 Apr 1996 14:25:25 +0100 (BST) From: Dirk-Jan Koopman X-Sender: djk@dns.leather.chbi.co.uk To: ss@tapr.org Subject: Re: [SS:183] Re: DS (or anything) key management In-Reply-To: <16D31FA0.1858@smtpgty.bwi.wec.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII On Thu, 11 Apr 1996, LANIER.R.A- wrote: > Dirk, > > One method you could use would be to limit the Pn sequences amateurs > use. Here in the states we are allowed only three, but I hope that > will change in the future :) . There are many such ways this can be > implemented, but the most successful will be the easiest. SS is > difficult enough without adding some esoteric descrambling algothrim > into the mix! > I don't much like this idea 'cos I really would like not to limit the PN sequences available. In any case, our licencing authorities try not to pose limitations of this sort because it is too limiting. This is why we have no limitations as to digital protocol here in the UK (ie we don't _need_ to use AX25 for everything). > Another possible idea is to give each user a unique address and with > that address a particular PN sequence picked from a general "database" > of PN sequences. This could be used in a net-like atmosphere, where > only individuals of a given net have a particular PN sequence. For > example, addresses 000-099 could use PN sequence [7,1], addresses > 100-199 could use PN sequence [13,4,3,1] and so on. In an ideal world I would like to have a (series of) 'scannable' PN sequence generating algorithm. The idea would be to have a standard algorithm which can take a number from 0-nnn(n..) and generate a sequence. A receiver could then have a 'dial' which you would 'twiddle' to scan the range of PN sequences in exactly the same way as you would twiddle the dial of your favourite receiver. This assumes you would remain on the same frequency - of course you then have the problem of dealing with multiple frequencies. My problem is that my maths isn't sufficient to deal with this problem. I am sure it is do-able, I just don't know how - hence my plea on this list. To make it easier (possibly), I don't need an exact algorithm for the purposes of getting things moving over here - what I am looking for is a protocol (in the political/discussion sense) of how to make _publicly_ available any PN sequences being used. The crucial licencing point is that any suitably equipped amateur must, relatively easily, be able to resolve any signal from any other amateur. If there is a form of words that achieves this then this would unlock our regulatory gates. Can anyone help? Dirk From LANIER.R.A-@smtpgty.bwi.wec.com Fri Apr 12 09:40:44 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id JAA09152 for ; Fri, 12 Apr 1996 09:40:39 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA20554; Fri, 12 Apr 1996 10:37:00 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16E6B930; Fri, 12 Apr 96 10:41:23 -0400 Mime-Version: 1.0 Date: Fri, 12 Apr 1996 10:42:09 -0400 Message-Id: <16E6B930.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:189] Stanford Telelcom part 2 To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part What is the URL for this web page? ______________________________ Reply Separator _________________________________ Subject: [SS:189] Stanford Telelcom part 2 Author: ss@tapr.org at BALT.SMTP Date: 4/12/96 8:16 AM from the Wireless & Cable Products Group (WCP) page: Wireless Communications Spread spectrum wireless communications, once the exclusive purview of the military, has come into its own with applications ranging from CDMA phones, cordless PBX systems, vehicle positioning, and wireless LANS. A spread spectrum system transmits both voice and data by spreading signals throughout the radio spectrum, often by employing direct-sequence modulation. Direct-sequence modulation (WCP's preferred method) transmits a high bit-rate pseudo-random code interspersed with the data signals over a broad bandwidth. This produces a highly efficient output that is much more difficult to decipher than linear, single-frequency transmissions. The receiving end efficiently recombines the dispersed and differentially transmitted signals, reproducing the original analog signal. Spread spectrum provides a secure transmission that is highly noise-resistant. A 1995 focus group study conducted by IDC, "Small Business and 13 Corporation Wireless Data Applications and Services, showed that, though only 4.5% of the participants had already installed wireless LANS, 52.5% were in the evaluation process or about to implement Wireless LANs in their corporations. WCP is providing wireless LAN architectures currently being adopted in Europe by ETSI. Stanford Telecom has been a leader in spread spectrum since its inception. The company's founders were instrumental in developing the fundamental waveforms for this technology. Today, WCP provides products for wireless local loop CDMA telephony, like "Airspan," a wireless telephone system developed by DSC Communications that is used by British Telephone and International TelCell, among others. Stanford Telecom's CDMA architecture is based on a patented orthogonal CDMA technology that greatly reduces the effect of signal multipath interference. In vehicle tracking and positioning, WCP spread spectrum products are being used in applications including tracking police cars and taxis, providing GPS/cellular vehicle assistance service, and other vehicle positioning systems. Spread Spectrum Wireless Communications Products STEL-2000A: This fast acquisition, wireless burst processor provides IF to TX/RX data on a single chip. It automatically tracks the carrier and processes data at rates up to 2.048 Mbps. - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From LANIER.R.A-@smtpgty.bwi.wec.com Fri Apr 12 09:51:21 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id JAA10134 for ; Fri, 12 Apr 1996 09:51:16 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA22201; Fri, 12 Apr 1996 10:47:46 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16E6E260; Fri, 12 Apr 96 10:52:22 -0400 Mime-Version: 1.0 Date: Fri, 12 Apr 1996 10:47:35 -0400 Message-Id: <16E6E260.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:191] Possible SS modem To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Do they have a web page or a catalog? Tony, KE4ATO ______________________________ Reply Separator _________________________________ Subject: [SS:191] Possible SS modem Author: ss@tapr.org at BALT.SMTP Date: 4/12/96 8:17 AM >From Randy's SSS online mag... Digital Wireless Corporation, Norcross, GA recently announced its new WIT2400 SS OEM frequency hopping transceiver with "12 dB More Receive Sensitivity" (more than a "wet Noodle?"). They also have the WIT915 with a full one Watt output power available. For more information, contact them at TEL: +1 770-564-5540 or FAX: +1 770-564-5541 -- I really think they have a pretty good product! I'll phone them for a quote. Any thoughts from the group? - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From jra1854@tntech.edu Fri Apr 12 09:54:07 1996 Received: from tntech.edu (SYSTEM@gemini.tntech.edu [149.149.11.7]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id JAA10425 for ; Fri, 12 Apr 1996 09:53:59 -0500 (CDT) Received: from [149.149.42.11] ("port 1169"@cookie-monster.ece.tntech.edu) by tntech.edu (PMDF V5.0-5 #11446) id <01I3G7J3L3Q8QS3IKJ@tntech.edu> for ss@tapr.org; Fri, 12 Apr 1996 09:52:24 -0500 (CDT) Date: Fri, 12 Apr 1996 09:52:23 -0600 From: jra1854@tntech.edu (Jeffrey Austen) Subject: Re: Does DSSS actually reduce AWGN ? X-Sender: jra1854@gemini.tntech.edu To: ss@tapr.org Message-id: MIME-version: 1.0 Content-type: text/plain; charset="us-ascii" Content-transfer-encoding: 7BIT > Also, aren't your involved in a receiver project for the PANSAT > satellite? How is that coming along? Yes. A bit of background first. I am teaching a senior telecommunications course here at TTU (visit us via the World-Wide Web at http://www.tntech.edu/). As part of the course we need to have a "major design project." This semester we chose to build the basic parts of a PANSAT receiver. The enrollment is quite small, being only four students (no falling asleep in my class!), so the scope of the project had to be limited. We did not address the down conversion or amplification part of the receiver since those parts can be readily obtained "off the shelf." The project involves taking in 21.4 MHz SS signal, with doppler shift still present, and despreading and demodulating it. I constructed a test transmitter, using a 16V8 PAL and a Mini-Circuits mixer, which generates the PN sequence, synchronization pulse, and modulates the output of a signal generator. The students task is to demodulate that signal. As the PANSAT design is based on packet radio and uses ARQ (automatic repeat request (or query)) for error control I imposed stringent synchronization time specifications on the project. It turns out that these specifications are complicating the design; actually the real problem is that ARQ and SS in general do not go well together because it takes some time to obtain code synchronization unless special techniques are used. The design and simulation phases are complete. Construction and testing are now being performed. The project will terminate at the end of the semester and I'll report on it some time after that. > I would like to know your references for the discussion below. I would > like to know more... The best place to start is one of many digital communications books that devote at least a chapter to SS. There are also some tutorial papers. They are: Scholtz, R. A., The Spread Spectrum Concept, IEEE Trans. Commun., vol. COM-25, pp. 748-755, August 1977. Pickholtz, R. L., Schilling, D. L., and Milstein, L. B., Theory of Spread Spectrum Communications - A Tutorial, IEEE Trans. Commun., vol. COM-30, PP. 855-884, May 1982. Viterbi, A. J., Spread Spectrum Communication - Myths and Realities, IEEE Commun. Magazine, vol. 17, pp. 11-18, May 1979. Viterbi, A. J., When not to Spread Spectrum - A Sequel, IEEE Commun. Magazine, vol. 23, pp. 12-17, April 1985. After that there are some more specialized books. They are: Introduction to Spread Spectrum Communications, R. L. Peterson, R. E. Ziemer, and D. E. Borth, Prentice-Hall, 1995. This book is for "anyone having previous courses on basic communication theory ... Fourier theory ... probability and random processes." It is targeted for teaching at the graduate and senior undergraduate levels. After an introductory chapter on digital communications and a chapter introducing SS systems it goes into details on various topics important to SS. The other chapters are: code sequence generators, initial synchronization, tracking, performance in a jamming environment (note that "jamming" includes interfering sources), forward error correction, fading, CDMA, and low probability of intercept. I recommend this book and for anybody doing experimenting with SS systems I would say this book is a necessity. CDMA: Principles of Spread Spectrum Communication, A. J. Viterbi, Addison-Wesley, 1995. The author states that the reader should have "at least an undergraduate electrical engineering background with some probability and communication engineering content." But then he goes on to say that "graduate course in communication theory ... would be preferable." I believe the second sentence is much closer to reality for two reasons: scope and mathematical level. This book does not provide much of an introduction to SS systems but instead almost immediately dives into the details; the reader without a basic understanding will quickly be lost. There is much use of probability and random processes and a reader not comfortable with these concepts will also be lost. This is a very good book but I would not recommend it to a person who does not have the necessary background. Wireless Digital Communications: Modulation and Spread Spectrum Applications, K. Feher, Prentice-Hall, 1995. The only reason I am listing this book is that it was mentioned in a previous message. It is more of an overview of "wireless" (funny how that term is now in vogue ... again) communications with some emphasis on mobile and cellular systems. The level of this book is senior undergraduate and beginning graduate and the mathematical level is lower than either of the two books listed above. There is only one chapter on Spread Spectrum, totaling about 45 pages. Other topics are: digital modulation, speech coding, cellular concepts and coding. One thing which the reader will notice almost immediately is that Feher has several patents, such as FQPSK (Feher's QPSK), and it is obvious that one of the goals of writing this book is to make sure that the world knows about them. One appendix is devoted specifically to it, which would be alright if that was all, but it also pervades the text. This probably biases me slightly against the book but, regardless, I would not particularly recommend this book as there are others which do a better job of covering most of the topics. Don't forget to look at Steven Bible's SS pages on the World-Wide Web. He has put together a large list of references. They can be found via the TAPR home page, http://www.tapr.org/ (I think). Jeff, k9ja --- Jeffrey Austen | Tennessee Technological University jra1854@tntech.edu | Box 5004 +1 615 372 3485 | Cookeville Tennessee 38505 U.S.A. From jra1854@tntech.edu Fri Apr 12 10:02:03 1996 Received: from tntech.edu (gemini.tntech.edu [149.149.11.7]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id KAA10609 for ; Fri, 12 Apr 1996 10:01:56 -0500 (CDT) Received: from [149.149.42.11] ("port 1345"@cookie-monster.ece.tntech.edu) by tntech.edu (PMDF V5.0-5 #11446) id <01I3G7U8N57KQS41UK@tntech.edu> for ss@tapr.org; Fri, 12 Apr 1996 10:01:23 -0500 (CDT) Date: Fri, 12 Apr 1996 10:01:22 -0600 From: jra1854@tntech.edu (Jeffrey Austen) Subject: Re: [SS:187] Re: PN sequencer X-Sender: jra1854@gemini.tntech.edu To: ss@tapr.org Message-id: MIME-version: 1.0 Content-type: text/plain; charset="us-ascii" Content-transfer-encoding: 7BIT > This same type of thing can be also be accomplished inside a PLD. The Yes, PLDs are nice. Unfortunately the programmers are not cheap. > I received a note from Bob Buaas on this subject. The inverter is > needed to fullfill the PN sequence equation: x^7 + x + 1. The +1 part > is the inverter; otherwise the sequence would converge after 127 clock > pulses. I'll will into this matter some more... No. The inverter is not necessary. Try the following. Case 1: Original circuit, start with all zeros in the shift register. Case 2: Same circuit except replace the inverter with a wire, start with all ones in the shift register. Both generate a maximal length sequence. In fact, one sequence is the inversion of the other. This is an interesting and non-intuitive result. Jeff, k9ja --- Jeffrey Austen | Tennessee Technological University jra1854@tntech.edu | Box 5004 +1 615 372 3485 | Cookeville Tennessee 38505 U.S.A. From LANIER.R.A-@smtpgty.bwi.wec.com Fri Apr 12 10:02:42 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id KAA10647 for ; Fri, 12 Apr 1996 10:02:31 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA22756; Fri, 12 Apr 1996 10:58:38 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16E70B80; Fri, 12 Apr 96 11:03:20 -0400 Mime-Version: 1.0 Date: Fri, 12 Apr 1996 10:57:23 -0400 Message-Id: <16E70B80.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:190] SS Books - Must haves To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part I have the book by Peterson, Ziemer, and Borth. It is a good book, but it has *ALOT* of math! Not for the lighthearted! I contacted Ziemer, who is a professor of engineer in Colorado, and he sent me a solutions manual to the problems in the book. Having them helps to know that you are working the problems correctly. The first several chapters are readable, but take off exponentially after that! Dixon's book is probably the best practical book I have found so far. It is the only book I have seen that includes actual oscilloscope screen photos. This is a definite plus. I would recommend this one second to the ARRL SS Sourcebook. The sourcebook helps to get your feet wet, I think. Then Dixon's book and then ... ? 73s de Tony, KE4ATO ______________________________ Reply Separator _________________________________ Subject: [SS:190] SS Books - Must haves Author: ss@tapr.org at BALT.SMTP Date: 4/12/96 8:16 AM Here are are three SS books I recommend. All three are must haves: "THE" Reference Book (revised from a previous 3 vol set): Spread Spectrum Communications Handbook, Revised Edition by Marvin K. Simon, Jim K. Omura, Robert A. Scholtz, and Barry K. Levitt McGraw-Hill, 1994 ISBN: 0-07-057629-7 Price: US$ 99.50 Excellent text, theory and mathematical: Introduction to Spread Spectrum Communications, 1/e by Rodger L. Peterson, Rodger E. Ziemer, and David E. Borth Prentice Hall, 1995 ISBN: 0-201-431623-7 Price: US$ 82.00 Practically oriented, Dixon is a "father" (of sorts) of civilian SS: Spread Spectrum Systems with Commercial Applications, 3rd Ed. by Robert C. Dixon John Wiley & Sons, 1994 ISBN: 0-471-59342-7 Price: US$ 79.95 - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From wb9mjn@wb9mjn.ampr.org Fri Apr 12 10:33:07 1996 Received: from wb9mjn.ampr.org (wb9mjn.ampr.org [44.72.98.19]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id KAA12306 for ; Fri, 12 Apr 1996 10:32:51 -0500 (CDT) From: wb9mjn@wb9mjn.ampr.org Date: Fri, 12 Apr 96 10:02:35 UTC Message-Id: <9762@wb9mjn.ampr.org> To: ss@tapr.org Subject: Re: [SS:195] Re: Does DSSS actually reduce AWGN ? In-Reply-To: your message of Fri Apr 12 10:08:20 1996 Hi Jeff, About that sleeping in class! Look who is talking?! Hi Hi hi.... 73, Don. Mailbox : WB9MJN @ N9HSI.IL.USA.NA AMPRNet : wb9mjn@wb9mjn.ampr.org[44.72.98.19] Internet: wb9mjn%wb9mjn.ampr.org@uugate.aim.utah.edu From n7hpr@tapr.org Fri Apr 12 12:00:51 1996 Received: from polaris.mindport.net (root@polaris.mindport.net [205.219.167.2]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id MAA17383 for ; Fri, 12 Apr 1996 12:00:47 -0500 (CDT) Received: from avatar.greene.net (ppp8.greene.net [206.96.97.108]) by polaris.mindport.net (8.6.12/8.6.12) with SMTP id NAA20054 for ; Fri, 12 Apr 1996 13:00:42 -0400 Posted-Date: Fri, 12 Apr 1996 13:00:42 -0400 Message-Id: <1.5.4b12.32.19960412170048.006964fc@mindport.net> X-Sender: srbible@mindport.net X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 12 Apr 1996 13:00:48 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: Re: [SS:194] Re: Possible SS modem At 10:07 AM 4/12/96 -0500, you wrote: > Do they have a web page or a catalog? > Not that I could find using normal search engines. - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From n7hpr@tapr.org Fri Apr 12 12:03:24 1996 Received: from polaris.mindport.net (root@polaris.mindport.net [205.219.167.2]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id MAA17682 for ; Fri, 12 Apr 1996 12:03:19 -0500 (CDT) Received: from avatar.greene.net (ppp8.greene.net [206.96.97.108]) by polaris.mindport.net (8.6.12/8.6.12) with SMTP id NAA20167 for ; Fri, 12 Apr 1996 13:03:13 -0400 Posted-Date: Fri, 12 Apr 1996 13:03:13 -0400 Message-Id: <1.5.4b12.32.19960412170319.00690104@mindport.net> X-Sender: srbible@mindport.net X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 12 Apr 1996 13:03:19 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: Re: [SS:193] Re: Stanford Telelcom part 2 At 09:43 AM 4/12/96 -0500, you wrote: > What is the URL for this web page? http://www.stel.com Then search for the Wireless & Cable Products Group (WCP) page. - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From djk@chbi.co.uk Fri Apr 12 12:45:11 1996 Received: from dns.chbi.co.uk (root@dns.chbi.co.uk [194.72.251.2]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id MAA19092 for ; Fri, 12 Apr 1996 12:45:06 -0500 (CDT) Received: from dns.leather.chbi.co.uk (dns.leather.chbi.co.uk [192.168.0.3]) by dns.chbi.co.uk (8.7.1/8.7.1) with ESMTP id RAA29119 for ; Fri, 12 Apr 1996 17:45:11 +0100 Received: (from djk@localhost) by dns.leather.chbi.co.uk (8.7.1/8.7.1) id RAA16456; Fri, 12 Apr 1996 17:48:32 +0100 Date: Fri, 12 Apr 1996 17:48:32 +0100 (BST) From: Dirk-Jan Koopman X-Sender: djk@dns.leather.chbi.co.uk To: ss@tapr.org Subject: Re: [SS:191] Possible SS modem In-Reply-To: <1.5.4b12.32.19960412125930.0069220c@mindport.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII How much? :-) On Fri, 12 Apr 1996, Steven R. Bible wrote: > >From Randy's SSS online mag... > > Digital Wireless Corporation, Norcross, GA recently announced its new > WIT2400 SS OEM frequency hopping transceiver with "12 dB More Receive > Sensitivity" (more than a "wet Noodle?"). They also have the WIT915 with a > full one Watt output power available. For more information, contact them at > TEL: +1 770-564-5540 or FAX: +1 770-564-5541 -- I really think they have a > pretty good product! > > I'll phone them for a quote. Any thoughts from the group? > > - Steve, N7HPR > > n7hpr@amsat.org > n7hpr@tapr.org > From LANIER.R.A-@smtpgty.bwi.wec.com Fri Apr 12 14:44:56 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id OAA23114 for ; Fri, 12 Apr 1996 14:44:39 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA12968; Fri, 12 Apr 1996 15:37:37 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 16EB2960; Fri, 12 Apr 96 15:44:22 -0400 Mime-Version: 1.0 Date: Fri, 12 Apr 1996 15:36:45 -0400 Message-Id: <16EB2960.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: Re: [SS:196] Re: PN sequencer To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Jeff, The inverter IS needed assuming that you will reset the shift register (set the outputs to all zero's). The invert would not be needed if the shift register is preset (set the outputs to all one's). The assumption was never stated and hence the confusion. 73s de Tony, KE4ATO ______________________________ Reply Separator _________________________________ Subject: [SS:196] Re: PN sequencer Author: ss@tapr.org at BALT.SMTP Date: 4/12/96 10:08 AM > I received a note from Bob Buaas on this subject. The inverter is > needed to fullfill the PN sequence equation: x^7 + x + 1. The +1 part > is the inverter; otherwise the sequence would converge after 127 clock > pulses. I'll will into this matter some more... No. The inverter is not necessary. Try the following. Case 1: Original circuit, start with all zeros in the shift register. Case 2: Same circuit except replace the inverter with a wire, start with all ones in the shift register. Both generate a maximal length sequence. In fact, one sequence is the inversion of the other. This is an interesting and non-intuitive result. Jeff, k9ja --- Jeffrey Austen | Tennessee Technological University jra1854@tntech.edu | Box 5004 +1 615 372 3485 | Cookeville Tennessee 38505 U.S.A. From n7hpr@tapr.org Tue Apr 16 18:29:34 1996 Received: from polaris.mindport.net (root@polaris.mindport.net [205.219.167.2]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id SAA08029 for ; Tue, 16 Apr 1996 18:29:30 -0500 (CDT) Received: from avatar.greene.net (ppp18.greene.net [206.96.97.118]) by polaris.mindport.net (8.6.12/8.6.12) with SMTP id TAA06178 for ; Fri, 12 Apr 1996 19:06:11 -0400 Posted-Date: Fri, 12 Apr 1996 19:06:11 -0400 Message-Id: <1.5.4b12.32.19960412230614.0069ab68@mindport.net> X-Sender: srbible@mindport.net X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 12 Apr 1996 19:06:14 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: OEM SS Transceiver Reference my earlier posting... I phoned Digital Wireless Corp. today and spoke with Tyler Churchill. She was very help and faxed me some information on their two OEM products. She is also sending in the mail more information. Here's what they have... Digital Wireless Corp. One Meca Way Norcross, GA 30093 Phone: 770-564-5540 Fax: 770-564-5541 ------------------------------------------------------------------------ Model No. WIT915 - Wireless Industrial Transceiver The literature says that the WIT915 uses a patented, proprietary form of spread spectrum technology called "Recombiant Spread Spectrum (RSS). Operating Modes: - Asynchronous data rates user selectable 300 bps to 38400 bps - Synchronous data rates user selectable 300 bps to 38400 bps - Asych or Synchronous mode user selectable - RF power output: user select either 1mW, 10mW, 100mW or 1W. Adaptive Transmit Power (full duplex) provides automatic scaling to the minimum power necessary to maintain high link quality. - RF channel: user select one of 21 available, non-overlapping frequency channels. Frequency Agility (full duplex) enables transceivers to automatically move to a clear channel in case of interference. - Half or full-duplex, user selectable. - The WIT915 offers a carrier detect signal (DCD) with a random backoff period which can be used to implement a CSMA network. General Specifications: - RF Frequency - 902-928 MHz - Part 15 - Operating Range - 1000 feet typical, over one mile line of sight - Serial Data Interface - Asynchronous or Synchronous Data - I/O Data Rate - 52.38 Kbps - RF Bandwidth - 1MHz - Number of Frequency Channels - 21 - Wakeup TIme - From Powerup - 54 ms - From Sleep Mode - 21 ms - Turnaround Time (Half-Duplex) - Transmit -> Receive - <500 us - Receive -> Transmit - <500 us - Transmit Power - Adjustable from 1mW to 1 W - Supply Voltage - 7.0 V min, 8.4 V nominal, 10.0 V max - Current Drain (Typical) - Half-Duplex Transmit - 195 mA to 452 mA Receive - 122 mA - Full-Duplex Receive/Transmit - 158 mA to 286 mA Receive Only - 122 mA - Sleep Mode - 750 uA Physical Dimensions - 2.3" x 2.9" x .8" Weight - 4.5 oz. (without antenna) Operating Temperature - 0 deg C to 70 deg C Humidity - 20% to 90% (non-condensing) Accessories: - RS-232 Interface Adapter Board - Battery Charger Board - 1/4 Wave Rubber Whip Antenna - Inverted-F Planar Antenna Prices: - Package unit - $850.00 each (first 2 units) (includes RS-232 adapter, power supply, batter backup, antenna and software) **** For a limited time **** (Cash/COD/Mastercard/Visa) $700.00 per unit, limit 2. - 1-99 $720.00 each ($80.00 for RS-232 Adapter) - 100-499 $640.00 each ($65.00 for RS-232 Adapter) - 500-999 $540.00 each ($55.00 for RS-232 Adapter) - 1K+ $440.00 each ($50.00 for RS-232 Adapter) ------------------------------------------------------------------------ Model WIT2400 Frequency Hopping Transceiver - Asynchronous or syschronous serial data interface - Either point-to-point or multipoint operation - up to 115 kbps data rate - Supports up to 255 nodes on a single network channel - License free operation in the 2400-2483 MHz band - Error free network protocol using Automatic Repeat Request (ARQ) and Forward Error Correction (FEC) - Range is typically 300-400 feet indoors and 1000 feet outdoors for line-of-site operation General Specifications: - 2400-2483 MHz - Network Topology - Star network - Network Protocol - CSMA/CA with ARQ and FEC - Serial Data Interface - Asynchronous (RS-232) or synchronous CMOS levels - I/O Data Rate - Up to 115 Kbps, half duplex - Channel Data Rate - 250 Kbps - Number of Frequency Channels - 82 - RF Bandwidth - 400 KHz - Transmit Power Output - 10 mW or 100 mW, programmable - Receiver Sensitivity - -95 bDm - Supply Voltage - 5.5 V to 9 V - Current Consumption - Remote Station 16 mA - 145 mA; 25 mA typ avg operating current - Physical Diamensions - 2.3" x 2.9" x 0.7" - Weight - 6 oz (without antenna) - Operating Temp - -20 deg C to 70 deg C - Humidity - 20% to 90% (non-condensing) Prices: - Package Sample Units - $850.00 each (first 2 units) (includes RS-232 adapter, power supply, batter backup, antenna and software) **** For a limited time **** (Cash/COD/Mastercard/Visa) $700.00 per unit, limit 2. - 1-99 $590.00 each - 100-249 $525.00 each - 250-499 $480.00 each - 500-749 $440.00 each - 750-999 $395.00 each - 1K+ $360.00 each ------------------------------------------------------------------------ Barry tells me that Proxim has an OEM SS modem. OEM RangeLAN2 1.6 Mbps 2.4 GHz FH modem http://www.proxim.com/proxim/products/oem/oem.htm Don't know the prices. ------------------------------------------------------------------------ - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From n7hpr@tapr.org Tue Apr 16 18:29:43 1996 Received: from polaris.mindport.net (root@polaris.mindport.net [205.219.167.2]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id SAA08046 for ; Tue, 16 Apr 1996 18:29:36 -0500 (CDT) Received: from avatar.greene.net (ppp18.greene.net [206.96.97.118]) by polaris.mindport.net (8.6.12/8.6.12) with SMTP id TAA05979; Fri, 12 Apr 1996 19:03:32 -0400 Posted-Date: Fri, 12 Apr 1996 19:03:32 -0400 Message-Id: <1.5.4b12.32.19960412230335.0068f174@mindport.net> X-Sender: srbible@mindport.net X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 12 Apr 1996 19:03:35 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: Re: [SS:191] Possible SS modem Cc: Dan E Carlisle Hello Dan, Spread Spectrum Scene is at http://www.sss-mag.com For other spread spectrum related web pages see http://www.tapr.org/ss/other.html - Steve N7HPR At 03:49 PM 4/12/96 -0500, you wrote: >What is the URL for "Randy's SSS online mag"? >Thanks. > >Dan Carlisle, WK8L >dec@cellcom.com > >On Fri, 12 Apr 1996, Steven R. Bible wrote: > >> >From Randy's SSS online mag... >> >> Digital Wireless Corporation, Norcross, GA recently announced its new >> WIT2400 SS OEM frequency hopping transceiver with "12 dB More Receive >> Sensitivity" (more than a "wet Noodle?"). They also have the WIT915 with a >> full one Watt output power available. For more information, contact them at >> TEL: +1 770-564-5540 or FAX: +1 770-564-5541 -- I really think they have a >> pretty good product! >> >> I'll phone them for a quote. Any thoughts from the group? >> >> - Steve, N7HPR >> >> n7hpr@amsat.org >> n7hpr@tapr.org > > > > > - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org From srbible@gnatnet.net Tue Apr 16 19:16:12 1996 Received: from denny.gnatnet.net (root@denny.gnatnet.net [206.30.198.7]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id TAA11704 for ; Tue, 16 Apr 1996 19:14:50 -0500 (CDT) Received: from gumby.gnatnet.net (dialup40.gnatnet.net [206.30.198.140]) by denny.gnatnet.net (8.6.12/8.6.9) with SMTP id UAA23050 for ; Tue, 16 Apr 1996 20:19:11 -0400 Message-Id: <1.5.4b12.32.19960417001426.00677c6c@gnatnet.net> X-Sender: srbible@gnatnet.net (Unverified) X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Tue, 16 Apr 1996 20:14:26 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: OEM SS Transceivers Reference my earlier posting... I phoned Digital Wireless Corp. today and spoke with Tyler Churchill. She was very help and faxed me some information on their two OEM products. She is also sending in the mail more information. Here's what they have... Digital Wireless Corp. One Meca Way Norcross, GA 30093 Phone: 770-564-5540 Fax: 770-564-5541 ------------------------------------------------------------------------ Model No. WIT915 - Wireless Industrial Transceiver The literature says that the WIT915 uses a patented, proprietary form of spread spectrum technology called "Recombiant Spread Spectrum (RSS). Operating Modes: - Asynchronous data rates user selectable 300 bps to 38400 bps - Synchronous data rates user selectable 300 bps to 38400 bps - Asych or Synchronous mode user selectable - RF power output: user select either 1mW, 10mW, 100mW or 1W. Adaptive Transmit Power (full duplex) provides automatic scaling to the minimum power necessary to maintain high link quality. - RF channel: user select one of 21 available, non-overlapping frequency channels. Frequency Agility (full duplex) enables transceivers to automatically move to a clear channel in case of interference. - Half or full-duplex, user selectable. - The WIT915 offers a carrier detect signal (DCD) with a random backoff period which can be used to implement a CSMA network. General Specifications: - RF Frequency - 902-928 MHz - Part 15 - Operating Range - 1000 feet typical, over one mile line of sight - Serial Data Interface - Asynchronous or Synchronous Data - I/O Data Rate - 52.38 Kbps - RF Bandwidth - 1MHz - Number of Frequency Channels - 21 - Wakeup TIme - From Powerup - 54 ms - From Sleep Mode - 21 ms - Turnaround Time (Half-Duplex) - Transmit -> Receive - <500 us - Receive -> Transmit - <500 us - Transmit Power - Adjustable from 1mW to 1 W - Supply Voltage - 7.0 V min, 8.4 V nominal, 10.0 V max - Current Drain (Typical) - Half-Duplex Transmit - 195 mA to 452 mA Receive - 122 mA - Full-Duplex Receive/Transmit - 158 mA to 286 mA Receive Only - 122 mA - Sleep Mode - 750 uA Physical Dimensions - 2.3" x 2.9" x .8" Weight - 4.5 oz. (without antenna) Operating Temperature - 0 deg C to 70 deg C Humidity - 20% to 90% (non-condensing) Accessories: - RS-232 Interface Adapter Board - Battery Charger Board - 1/4 Wave Rubber Whip Antenna - Inverted-F Planar Antenna Prices: - Package unit - $850.00 each (first 2 units) (includes RS-232 adapter, power supply, batter backup, antenna and software) **** For a limited time **** (Cash/COD/Mastercard/Visa) $700.00 per unit, limit 2. - 1-99 $720.00 each ($80.00 for RS-232 Adapter) - 100-499 $640.00 each ($65.00 for RS-232 Adapter) - 500-999 $540.00 each ($55.00 for RS-232 Adapter) - 1K+ $440.00 each ($50.00 for RS-232 Adapter) ------------------------------------------------------------------------ Model WIT2400 Frequency Hopping Transceiver - Asynchronous or syschronous serial data interface - Either point-to-point or multipoint operation - up to 115 kbps data rate - Supports up to 255 nodes on a single network channel - License free operation in the 2400-2483 MHz band - Error free network protocol using Automatic Repeat Request (ARQ) and Forward Error Correction (FEC) - Range is typically 300-400 feet indoors and 1000 feet outdoors for line-of-site operation General Specifications: - 2400-2483 MHz - Network Topology - Star network - Network Protocol - CSMA/CA with ARQ and FEC - Serial Data Interface - Asynchronous (RS-232) or synchronous CMOS levels - I/O Data Rate - Up to 115 Kbps, half duplex - Channel Data Rate - 250 Kbps - Number of Frequency Channels - 82 - RF Bandwidth - 400 KHz - Transmit Power Output - 10 mW or 100 mW, programmable - Receiver Sensitivity - -95 bDm - Supply Voltage - 5.5 V to 9 V - Current Consumption - Remote Station 16 mA - 145 mA; 25 mA typ avg operating current - Physical Diamensions - 2.3" x 2.9" x 0.7" - Weight - 6 oz (without antenna) - Operating Temp - -20 deg C to 70 deg C - Humidity - 20% to 90% (non-condensing) Prices: - Package Sample Units - $850.00 each (first 2 units) (includes RS-232 adapter, power supply, batter backup, antenna and software) **** For a limited time **** (Cash/COD/Mastercard/Visa) $700.00 per unit, limit 2. - 1-99 $590.00 each - 100-249 $525.00 each - 250-499 $480.00 each - 500-749 $440.00 each - 750-999 $395.00 each - 1K+ $360.00 each ------------------------------------------------------------------------ Barry tells me that Proxim has an OEM SS modem. OEM RangeLAN2 1.6 Mbps 2.4 GHz FH modem http://www.proxim.com/proxim/products/oem/oem.htm Don't know the prices. ------------------------------------------------------------------------ - Steve, N7HPR n7hpr@amsat.org n7hpr@tapr.org - Steve, N7HPR srbible@gnatnet.net n7hpr@amsat.org n7hpr@tapr.org From LANIER.R.A-@smtpgty.bwi.wec.com Wed Apr 17 16:12:30 1996 Received: from tron.bwi.wec.com (tron.bwi.wec.com [129.228.4.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id QAA05213 for ; Wed, 17 Apr 1996 16:12:09 -0500 (CDT) Received: from smtpgty.bwi.wec.com by tron.bwi.wec.com; (5.65/1.1.8.2/31May95-0229PM) id AA03785; Wed, 17 Apr 1996 11:15:19 -0400 Received: from ccMail by smtpgty.bwi.wec.com (IMA Internet Exchange 2.0 Beta 5) id 17551C20; Wed, 17 Apr 96 16:17:06 -0400 Mime-Version: 1.0 Date: Wed, 17 Apr 1996 16:13:57 -0400 Message-Id: <17551C20.1858@smtpgty.bwi.wec.com> From: LANIER.R.A-@smtpgty.bwi.wec.com (LANIER.R.A-) Subject: PN sequences To: ss@tapr.org Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Hello to all, I did some modeling of the PN sequence discussed last week. I used Electronic Workbench v4.1 for the modeling. As I thought, if the shift register is preset, then the inverter is not needed. I let this simulation run for several hours. No convergence to zero was found. I don't want to beat a dead horse, but just wanted to verify for myself what would happen. On another matter, has anyone done anything on data encoding/decoding? More specificly, I'm looking for plans for a Viterbi encoder/decoder. If you think another encoding scheme is better, I would like to hear from you. 73s de Tony, KE4ATO From Andrew.Burnside@durham.ac.uk Wed Apr 17 16:44:58 1996 Received: from hermes.dur.ac.uk ([129.234.4.9]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id QAA07899 for ; Wed, 17 Apr 1996 16:44:48 -0500 (CDT) Received: from venus by hermes.dur.ac.uk id (8.6.12/ for dur.ac.uk) with SMTP; Wed, 17 Apr 1996 15:51:09 +0100 Received: from altair by venus id ; Wed, 17 Apr 1996 15:51:08 +0100 Date: Wed, 17 Apr 1996 15:51:07 +0100 (BST) From: Andrew Burnside To: ss@tapr.org Subject: Re: [SS:135] Re: File your comments in RM-8737! In-Reply-To: <960309112329_346005451@mail06.mail.aol.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII On Sat, 9 Mar 1996 ATVQ@aol.com wrote: > Why do I need a $1000 computer for a $100 camera and still have no > transmitter/antenna, when I can use a $25 camera, a $99 transmitter and a $1 > antenna with a TV set I already own and have a complete two way video station > for under $150. Why exactly! Surely it would not be that hard to hook up a parallel port camera to a SS modem. This could be done with a simple PIC or other processor, to frame the data. This is an area which amateurs can again lead the path. Little work has been done on radio packet based Digital TV transmission. MPEG is of limited use here, since packets may arrive out of order, unless a large look-ahead buffer is used. > Get real! Hey computer video, fun toy, too big, too expensive, for us > common working folks. I can see why with dollars worth of analogue video equipment you are anxious to protect your investment, but please don't let that prejudice your views. In an earlier article you extolled the virtues of NTSC. This counteracts your claims of better quality for analogue video. Digital video is certainly much better than NTSC. On the availability of digital TV sets, we are bound to see them commonly available in the next few years, as digital cable and satellite channels come online. But in the interim why not contribute to the amateur community, and convert from digital to NTSC or RGB in your station. Andrew ------------------------------------------------------------------------------ You can only be knocked down if you are standing up. ------------------------------------------------------------------------------ Andrew.Burnside@durham.ac.uk ------------------------------------------------------------------------------ From srbible@gnatnet.net Wed Apr 17 19:29:43 1996 Received: from denny.gnatnet.net (root@denny.gnatnet.net [206.30.198.7]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id TAA17809 for ; Wed, 17 Apr 1996 19:29:40 -0500 (CDT) Received: from gumby.gnatnet.net (dialup36.gnatnet.net [206.30.198.136]) by denny.gnatnet.net (8.6.12/8.6.9) with SMTP id TAA16447 for ; Wed, 17 Apr 1996 19:33:04 -0400 Message-Id: <1.5.4b12.32.19960418002929.0067ba4c@gnatnet.net> X-Sender: srbible@gnatnet.net (Unverified) X-Mailer: Windows Eudora Light Version 1.5.4b12 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Wed, 17 Apr 1996 20:29:29 -0400 To: ss@tapr.org From: "Steven R. Bible" Subject: Any nibbles?? (was OEM SS Transceiver) I thought someone would comment on these prices. Granted the package price of $700.00 is steep, but consider how much it costs to put up a WA4DSY 56kbps node. Either of these modems would be faster yet the distance would be shorter. Comments? - Steve N7HPR ------------------------------------------------------------------------ Model No. WIT915 - Wireless Industrial Transceiver Prices: - Package unit - $850.00 each (first 2 units) (includes RS-232 adapter, power supply, batter backup, antenna and software) **** For a limited time **** (Cash/COD/Mastercard/Visa) $700.00 per unit, limit 2. - 1-99 $720.00 each ($80.00 for RS-232 Adapter) - 100-499 $640.00 each ($65.00 for RS-232 Adapter) - 500-999 $540.00 each ($55.00 for RS-232 Adapter) - 1K+ $440.00 each ($50.00 for RS-232 Adapter) ------------------------------------------------------------------------ Model WIT2400 Frequency Hopping Transceiver Prices: - Package Sample Units - $850.00 each (first 2 units) (includes RS-232 adapter, power supply, batter backup, antenna and software) **** For a limited time **** (Cash/COD/Mastercard/Visa) $700.00 per unit, limit 2. - 1-99 $590.00 each - 100-249 $525.00 each - 250-499 $480.00 each - 500-749 $440.00 each - 750-999 $395.00 each - 1K+ $360.00 each ------------------------------------------------------------------------ - Steve, N7HPR srbible@gnatnet.net n7hpr@amsat.org n7hpr@tapr.org From wd5ivd@tapr.org Wed Apr 17 20:42:30 1996 Received: (from wd5ivd@localhost) by tapr.org (8.7.5/8.7.3/1.9) id UAA21765 for ss@tapr.org; Wed, 17 Apr 1996 20:42:29 -0500 (CDT) From: Greg Jones Message-Id: <199604180142.UAA21765@tapr.org> Subject: Re: [SS:208] Any nibbles?? (was OEM SS Transceiver) To: ss@tapr.org Date: Wed, 17 Apr 1996 20:42:28 -0500 (CDT) In-Reply-To: <1.5.4b12.32.19960418002929.0067ba4c@gnatnet.net> from "Steven R. Bible" at Apr 17, 96 07:40:20 pm X-Mailer: ELM [version 2.4 PL25] Content-Type: text > I thought someone would comment on these prices. Granted the package price > of $700.00 is steep, but consider how much it costs to put up a WA4DSY > 56kbps node. Either of these modems would be faster yet the distance would > be shorter. > > Comments? > > - Steve N7HPR > > > - Package Sample Units - $850.00 each (first 2 units) > > - 1-99 $590.00 each > - 100-249 $525.00 each > - 250-499 $480.00 each > - 500-749 $440.00 each > - 750-999 $395.00 each > - 1K+ $360.00 each > > ------------------------------------------------------------------------ Hi Steve. As most of us know -- cost is everything in amateur radio. While most of us on this list will agree that $700 for what the unit provides is a reasonable price, to have impact on the amateur radio world we have to provide those things at the 1000 unit price of $360 listed. We have three populations to trace. We have amateurs who are: 1. end users and are moving to other perceived faster digital modes 2. networkers who have been and understand the price of making things work 3. experimenters who also understand the price of making things work The first item is about 90% (my guess) of digital users. The other two groups understand what doing digital communications over radio is about and can understand the problems and prices involved. The problem is that item 1 (90%) is one reason why the DSY system or other similarly priced systems have not been as popular or wide spread as you would think. Both price and the required technical know-how eliminates a lot of this group. This is probably a politically incorrect thing to say, but most hams are not willing to pay the price for the performance in this group. A good example of this are the amateurs who are leaving amateur digital radio because they can do faster speeds over the telephone, but are not willing to understand the differences between the telephone and radio media. Price is still an issue for group 2 because it limits the size and number of sites of the system they wish to implement. In addition, replacement units are less available for the system and in theory will produce longer downtime at sites. A higher price point means that group 2 and 3 will purchase units to experiment and learn with, but will not have a major impact on amateur operations. --- Considering the commercial price listed, that of $330 at 1000 units, I would guess that they have about $250 or less worth of investment in the hardware. Maybe someone familiar with the hardware can give a better estimate. I feel confident that amateurs can produce a SS radio and make it have real impact for the amateur community. If TAPR where to do this, the overhead of doing this type of system would be about a 40% market up for an amateur unit and have a price around $450-$500 if we assume the cost is $300 or less. This is well within the correct price range for local access and a high participation level. Once you involve the amateur commercial groups, who can do much larger volumes the price should drop further. We either work deals with commercial developers to get discounts for amateur experimentation and development (i.e. at the $300 to $400 price), which is hard to do because many business do not understand the relevant cross over between amateur and later commercial systems that are developed. Or we develop our own system -- which is more difficult and long term or we do something else ? --- After engineering it comes down to marketing. The issues become for a successful SS item in amateur radio: 1. unit has to at least do 38.4 or faster (all marketing based) 2. has to be a reliable design and rugged 3. has to be less than $500 -- more like $300 for most hams Those are the big issues in order to hit the 90% of the amateur population. My belief is that as experimenters it is important to push the envelope, but the final goal has to be to shot for something that can be used by the 90%. Many amateurs that do real work in advanced areas never pass along their work in a truly meaningful enough way in order to help the other 90% of the amateur community. Anyway --- that is enough rambling for now. Cheers - Greg From seanw@hpqs0212.sqf.hp.com Thu Apr 18 04:22:49 1996 Received: from paloalto.access.hp.com (daemon@paloalto.access.hp.com [15.254.56.2]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id EAA16573 for ; Thu, 18 Apr 1996 04:22:47 -0500 (CDT) Received: from hpqs0212.sqf.hp.com by paloalto.access.hp.com with ESMTP (1.37.109.16/15.5+ECS 3.3) id AA246539359; Thu, 18 Apr 1996 02:22:44 -0700 Received: by hpqs0212.sqf.hp.com (1.37.109.16/15.5+ECS 3.4 ) id AA089609358; Thu, 18 Apr 1996 10:22:38 +0100 From: Sean Warren-Cox (SWC) Message-Id: <199604180922.AA089609358@hpqs0212.sqf.hp.com> Subject: SS for position To: ss@tapr.org Date: Thu, 18 Apr 1996 10:22:38 BST X-Mailer: Elm [revision: 109.14] Hello Everybody, I am new to this group and I am trying to find out as much about Spread Spectrum Systems for accurate position identification. I cannot use GPS as I do not have line of sight to satellites. I would like to build a home grown transmitter(satellite) and receiver to measure distance and bearing to less than 1 cm accuracy. Note I do not have line of sight to my own transmitter either so I guess I will have to use frequencies < 3GHz. I have read around a bit, Spread Spectrum Systems with Commercial Applications by Dixon and GPS Satellite Surveying by Leick. Can anyone suggest books, articles, web sites where I might find practical information on building my own system. Many Thanks, Sean _______________________________________________________________________________ Sean Warren-Cox | sean@hpiplaa.sqf.hp.com TSD direct line | tel: 0131 331 7080 _______________________________________________________________________________ From gerry@cs.tamu.edu Thu Apr 18 10:56:49 1996 Received: from cs.tamu.edu (clavin.cs.tamu.edu [128.194.130.106]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id KAA28967 for ; Thu, 18 Apr 1996 10:56:46 -0500 (CDT) Received: from solar.cs.tamu.edu (2961@solar.cs.tamu.edu [128.194.132.1]) by cs.tamu.edu (8.6.10/8.6.4) with ESMTP id KAA12536 for ; Thu, 18 Apr 1996 10:56:05 -0500 From: Gerald J Creager Received: (gerry@localhost) by solar.cs.tamu.edu (8.6.10/8.6.4) id KAA21753 for ss@tapr.org; Thu, 18 Apr 1996 10:55:37 -0500 Message-Id: <199604181555.KAA21753@solar.cs.tamu.edu> Subject: Re: [SS:210] SS for position To: ss@tapr.org Date: Thu, 18 Apr 1996 10:55:36 -0500 (CDT) In-Reply-To: <199604180922.AA089609358@hpqs0212.sqf.hp.com> from "Sean Warren-Cox" at Apr 18, 96 04:38:39 am X-Mailer: ELM [version 2.4 PL25] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit I guess I'm a little baffled. Where do you not have good satellite coverage, but where you think you could do RF-based positioning without multipath? The overhead angles for GPS work are not very restrictive. 73, gerry n5jxs@tamu.edu From ATVQ@aol.com Thu Apr 18 14:23:50 1996 Received: from emout16.mail.aol.com (emout16.mx.aol.com [198.81.11.42]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id OAA03206 for ; Thu, 18 Apr 1996 14:23:47 -0500 (CDT) From: ATVQ@aol.com Received: by emout16.mail.aol.com (8.6.12/8.6.12) id MAA17680 for ss@tapr.org; Thu, 18 Apr 1996 12:26:57 -0400 Date: Thu, 18 Apr 1996 12:26:57 -0400 Message-ID: <960418122656_472792863@emout16.mail.aol.com> To: ss@tapr.org Subject: Re: [SS:207] Re: File your comments in RM-8737! Digital has yet to be better than NTSC. So far every digital system has digital artifacts these are visible defects in the picture. Jagged edges, blocks of movement that dont exist, loss of detail, and digital takes a lot more spectrum room than analog. Also if you look at the digital ATV (advanced TV) spectrum, it is solid noise in composition, not coherent sidebands as analog. Also the amplitude at every point inthe 6 MHz digital spectrum is filled, much like FM, whereas analog ntsc has a decreasing amplitude/frequency slope and thousands of "holes" and after 1 Mhz, the sideband energy of analog TV is insignificant vs no difference in "sideband" power for digital TV. The cheapest estimate for a digital TV set at NAB this year was $3500 (receive only) in mass quantities, deliverable in a few months if needed. I sure hate to pass by that $49 TV set at Sams's club to spend $3500 for digital madness. The best estimates at NAB were digital TV (so-called HDTV) in 5 years politically, and 25-40 years before NTSC is replaced by HDTV. So keep those cards and letters comming. Analog NTSC is plenty good if you use good analog NTSC equipment to rx/tx. There is NO visual improvement in detail on HDTV, only the aspect ratio changes. This is because of the resolution limits of our EYES at normal viewing distances. The improved resolution is only apparant on very large screen TV's which incorporate line doubling (a receiver modification which has nothing to do with analog or digital) to "erase" the scan lines and you can see the fuzzy out of focus camera work better. As for hams leading the digital way.....take the lead and write it up, I will publish it! But dont expect a stampede. 73 Henry From ka1kjz@tigger.jvnc.net Thu Apr 18 20:30:44 1996 Received: from tigger.jvnc.net (tigger.jvnc.net [128.121.50.145]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id UAA20505 for ; Thu, 18 Apr 1996 20:30:40 -0500 (CDT) Received: from ka1kjz.jvnc.net by tigger.jvnc.net with SMTP id AA06138 (5.65c/IDA-1.4.4 for ss@tapr.org); Thu, 18 Apr 1996 21:30:28 -0400 Date: Thu, 18 Apr 1996 21:30:28 -0400 Message-Id: <199604190130.AA06138@tigger.jvnc.net> X-Sender: ka1kjz@tigger.jvnc.net X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: ss@tapr.org From: "Ronald C. Barnes" Subject: Re: File your comments in RM-8737! At 02:26 PM 4/18/96 -0500, ATVQ@aol.com wrote: >Digital has yet to be better than NTSC. So far every digital system has >digital artifacts these are visible defects in the picture. Jagged edges, >blocks of movement that dont exist, loss of detail, and digital takes a lot >more spectrum room than analog. Also if you look at the digital ATV >(advanced TV) spectrum, it is solid noise in composition, not coherent >sidebands as analog. Also the amplitude at every point inthe 6 MHz digital >spectrum is filled, much like FM, whereas analog ntsc has a decreasing >amplitude/frequency slope and thousands of "holes" and after 1 Mhz, the >sideband energy of analog TV is insignificant vs no difference in "sideband" >power for digital TV. The cheapest estimate for a digital TV set at NAB this >year was $3500 (receive only) in mass quantities, deliverable in a few months >if needed. I sure hate to pass by that $49 TV set at Sams's club to spend >$3500 for digital madness. The best estimates at NAB were digital TV >(so-called HDTV) in 5 years politically, and 25-40 years before NTSC is >replaced by HDTV. > So keep those cards and letters comming. Analog NTSC is plenty good if >you use good analog NTSC equipment to rx/tx. There is NO visual improvement >in detail on HDTV, only the aspect ratio changes. This is because of the > resolution limits of our EYES at normal viewing distances. The improved >resolution is only apparant on very large screen TV's which incorporate line >doubling (a receiver modification which has nothing to do with analog or >digital) to "erase" the scan lines and you can see the fuzzy out of focus >camera work better. As for hams leading the digital way.....take the lead >and write it up, I will publish it! But dont expect a stampede. 73 Henry > > > Its amazing that a person who has NO CLUE as the ATSC's proposal for HDTV and of Digital Television in general can speak on such a subject with so much vehemence. Digital video has been proven, in many ways, on a daily basis for several years. Digital video is used by most major broadcasters either in the tape machine, or in distribution. I will answer each point in turn.... Motion artifacts are a consequence of digital compression rather than the sheer fact it is digital. In an MPEG-2 system, depending on the compression ratio used, no motion artifacts are visible. WOuld it suprise you to know that ALL of HBO's services (HBO, HBO-2, 3, etc, Cinemax, etc) are DIGITAL? Each channel is MPEG-2 compressed, actually DigiCipher 2 compressed, and sent to the satellite as a digital bitstream. HBO is not the only service to be DG2 compressed, Speedvision, Outdoor Life, TV Food Network and 5 of the 6 Viewer's Choice channels are distributed in this manner. There are many others digitally distributed, the list is endless. Also on the subject of digital compression, did you know that most of the top 40 ADI broadcast television stations and most cable networks are using digital VTRS? I just got back from the Sony training class on the DVW-A500 Digital Betacam VTR and that unit uses a 2:1 lossless compression of the data. In fact, DBETA is far superior in resolution than Analog Beta. Did you realize that the HBO services use D2 decks, using a lossless 2:1 compression, and TLC, Speedvision and Outdoor Life use DBETA with a similar 2:1 compression. As for terrestrial broadcasters, WWOR, Maryland and Ohio Public TV use DBETA, WTIC uses D2, and WPIX uses D3. So what if HDTV uses the spectrum more efficiently than analog NTSC? If you were to watch an NTSC channel on a storage spectrum analyser (only seen one in my life) you would notice that the spectrum does fill up much like a digital channel as the pictures sent via the NTSC channel vary with Average Picture Level and frequency content, over time. So what if there are no coherent sidebands, do we care? As for an estimate of $3500 for a digital TV at NAB this year, how can this be, NAB isnt over yet. Last estimate I got, was in the neighborhood of $1500, several years ago when the big 7 were competing to be THE standard. You of course realize that this price will drop as manufacturing volume increases, much like cellular phones, VCRs and Microwaves did after they were introduced. Yes, HDTV will take MANY years to implement. Did you realize that Great Britian took 20 years to change from the 400 line monochrome to the 625 color standard? There will be alot of simulcasting taking place during the implementation period. There certainly IS a visual improvement over NTSC. I once saw a demonstration of the DigiCipher HDTV standard side by side with NTSC. The HDTV picture was comparable with 35MM film while NTSC was its usual grainy self. I dont have the specs in front of me, but I'll take 1000 odd lines over 525 any day, and vertical lines of resolution are similarly higher. Line doubling?????? What is that??? Erasing the scan lines?? wouldnt that LOWER the resolution even more? I am confused here. In my years as a broadcast engineer, I have NEVER heard of this term. Write it up and it will be published, hopefully in a reputable magazine that is professionally laid out, proofread and spellchecked. Not a ransom note between two glossy covers. -- *********************************************************************** ** Ronald C. Barnes KA1KJZ Engineering Tech, Group W Satellite ** ** 1591 W. Broad Street ARRL CT Section Technical Coord. ** ** Stratford, CT 06497 Member, Soc. Broadcast Engineers ** ** ** ** The preceding was brought to you by Ouchies (tm) ** ** The prickly toy you bathe with ** *********************************************************************** From seanw@hpqs0212.sqf.hp.com Fri Apr 19 01:58:21 1996 Received: from paloalto.access.hp.com (daemon@paloalto.access.hp.com [15.254.56.2]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id BAA08882 for ; Fri, 19 Apr 1996 01:58:14 -0500 (CDT) Received: from hpqs0212.sqf.hp.com by paloalto.access.hp.com with ESMTP (1.37.109.16/15.5+ECS 3.3) id AA261987083; Thu, 18 Apr 1996 23:58:04 -0700 Received: by hpqs0212.sqf.hp.com (1.37.109.16/15.5+ECS 3.4 ) id AA103247079; Fri, 19 Apr 1996 07:57:59 +0100 From: Sean Warren-Cox (SWC) Message-Id: <199604190657.AA103247079@hpqs0212.sqf.hp.com> Subject: Re: [SS:211] Re: SS for position To: ss@tapr.org Date: Fri, 19 Apr 1996 7:57:59 BST In-Reply-To: <199604181555.KAA21753@solar.cs.tamu.edu>; from "Gerald J Creager" at Apr 18, 96 11:01 am X-Mailer: Elm [revision: 109.14] Hi Gerry, forgive my ignorance but I believe that satelite coverage requires line of sight with the sky and I want to measure positions within a building. Also I want to measure to within 1cm and this cannot be done with GPS without using P-code which is restricted for military use. So the only solution I can think of is to build my own satellite transmitters and receivers that with work within a building through solid walls. Multipath I agree is still going to be a problem. > > I guess I'm a little baffled. Where do you not have good satellite coverage, > but where you think you could do RF-based positioning without multipath? > > The overhead angles for GPS work are not very restrictive. > > 73, gerry > n5jxs@tamu.edu > > -- _____________________________________________________________________ Sean Warren-Cox | sean@hpiplaa.sqf.hp.com TSD direct line | tel: 0131 331 7080 _____________________________________________________________________ From wd5ivd@tapr.org Fri Apr 19 03:56:05 1996 Received: (from wd5ivd@localhost) by tapr.org (8.7.5/8.7.3/1.9) id DAA11600 for ss@tapr.org; Fri, 19 Apr 1996 03:56:04 -0500 (CDT) From: Greg Jones Message-Id: <199604190856.DAA11600@tapr.org> Subject: Re: [SS:214] Re: SS for position To: ss@tapr.org Date: Fri, 19 Apr 1996 03:56:04 -0500 (CDT) In-Reply-To: <199604190657.AA103247079@hpqs0212.sqf.hp.com> from "Sean Warren-Cox" at Apr 19, 96 02:03:11 am X-Mailer: ELM [version 2.4 PL25] Content-Type: text Steve Bible - who is on this list has co-authored a paper with one of his past profs at the Naval Post Graduate School concerning accurate positioning of this type with a small area. Not sure about a building, but remembert having a very smiliar dicussion with Steve on the possibility of simulating things in order to generate virtully maped spaces. This was all using SS. Steve just moved from CT to the south part of the US and is getting setteled in -- with luck he will post something and clear up my all but cluttered memory. Cheers - Greg, WD5IVD > > Hi Gerry, > > forgive my ignorance but I believe that satelite coverage requires line of > sight with the sky and I want to measure positions within a building. Also > I want to measure to within 1cm and this cannot be done with GPS without > using P-code which is restricted for military use. > So the only solution I can think of is to build my own satellite transmitters > and receivers that with work within a building through solid walls. > Multipath I agree is still going to be a problem. > > > > > I guess I'm a little baffled. Where do you not have good satellite coverage, > > but where you think you could do RF-based positioning without multipath? > > > > The overhead angles for GPS work are not very restrictive. > > > > 73, gerry > > n5jxs@tamu.edu > > > > > > > -- > _____________________________________________________________________ > > Sean Warren-Cox | sean@hpiplaa.sqf.hp.com > TSD direct line | tel: 0131 331 7080 > _____________________________________________________________________ > > From c-three@telepost.no Fri Apr 19 05:55:50 1996 Received: from netto.telepost.no (netto.telepost.no [193.212.1.11]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id FAA14396 for ; Fri, 19 Apr 1996 05:55:46 -0500 (CDT) Received: from c-three.telepost.no by netto.telepost.no with SMTP (8.6.13/nms1.1) id for ; Fri, 19 Apr 1996 12:55:42 +0200 Message-Id: <199604191055.2795.telepost.no@telepost.no> X-Sender: c-three@telepost.no X-Mailer: Windows Eudora Pro Version 2.1.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 19 Apr 1996 12:55:44 +0200 To: ss@tapr.org From: Per-Tore Aasestrand Subject: Re: [SS:214] Re: SS for position At 02:03 19.04.96 -0500, Sean Warren-Cox wrote: >Hi Gerry, > >forgive my ignorance but I believe that satelite coverage requires line of >sight with the sky and I want to measure positions within a building. Also >I want to measure to within 1cm and this cannot be done with GPS without >using P-code which is restricted for military use. >So the only solution I can think of is to build my own satellite transmitters >and receivers that with work within a building through solid walls. >Multipath I agree is still going to be a problem. The precision for the military code will be in the order of several meters! Applying differential techniques, this can be improved to within 30-50 cm. Since the radiowaves propagates at 30 cm/ns, 1 cm location precision would require a timing resolution of appr. 0.3 ns! Using DS-SS, you would use the chips as "markers", and you would measure the time delay between the chips received form the different "beacons" (or sattelites). Multipath will be a serious problem. What about the propagation properties of the different building materials? Will this have a significant influence on the absolute time delays? Interesting project, thou! Regards, Per-Tore LA7NO ----------------------------------+-------------------------------- | Per-Tore Aasestrand | E-mail : c-three@telepost.no | | C-Three Systems AS | Fax : + 47 - 55 23 18 88 | | P.O. Box 1708 | Voice : + 47 - 55 32 67 67 | | N-5024 Bergen, Norway | Mobile : + 47 - 92 04 44 76 | ----------------------------------+-------------------------------- From gerry@cs.tamu.edu Fri Apr 19 11:24:18 1996 Received: from cs.tamu.edu (clavin.cs.tamu.edu [128.194.130.106]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id LAA26633 for ; Fri, 19 Apr 1996 11:24:10 -0500 (CDT) Received: from solar.cs.tamu.edu (2961@solar.cs.tamu.edu [128.194.132.1]) by cs.tamu.edu (8.6.10/8.6.4) with ESMTP id LAA19926 for ; Fri, 19 Apr 1996 11:23:29 -0500 From: Gerald J Creager Received: (gerry@localhost) by solar.cs.tamu.edu (8.6.10/8.6.4) id LAA12924 for ss@tapr.org; Fri, 19 Apr 1996 11:22:58 -0500 Message-Id: <199604191622.LAA12924@solar.cs.tamu.edu> Subject: Re: [SS:214] Re: SS for position To: ss@tapr.org Date: Fri, 19 Apr 1996 11:22:57 -0500 (CDT) In-Reply-To: <199604190657.AA103247079@hpqs0212.sqf.hp.com> from "Sean Warren-Cox" at Apr 19, 96 02:03:11 am X-Mailer: ELM [version 2.4 PL25] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sean Warren-Cox sez: > > forgive my ignorance but I believe that satelite coverage requires line of > sight with the sky and I want to measure positions within a building. Also > I want to measure to within 1cm and this cannot be done with GPS without > using P-code which is restricted for military use. > So the only solution I can think of is to build my own satellite transmitters > and receivers that with work within a building through solid walls. > Multipath I agree is still going to be a problem. You are, of couorse, correct: You have to see the sky to get GPS coverage. Off hand, I suspect your best option is transponder-triangulation: Ping the position transponder with 3-4 fixed beacons and derive the position info from that. Then, you're just reducing it to timing. 73, gerry From ATVQ@aol.com Fri Apr 19 11:24:40 1996 Received: from emout08.mail.aol.com (emout08.mx.aol.com [198.81.11.23]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id LAA26689 for ; Fri, 19 Apr 1996 11:24:36 -0500 (CDT) From: ATVQ@aol.com Received: by emout08.mail.aol.com (8.6.12/8.6.12) id MAA18158 for ss@tapr.org; Fri, 19 Apr 1996 12:24:04 -0400 Date: Fri, 19 Apr 1996 12:24:04 -0400 Message-ID: <960419122402_473561898@emout08.mail.aol.com> To: ss@tapr.org Subject: Re: [SS:213] Re: File your comments in RM-8737! Shows what you dont know. I have been at every HDTV demo/test. So I think I know a lot more about it than you. Also NAB is OVER, I was there too. 1. Digital is not "proven" as you claim. It is USED, because it offers some things in RECORDING that are not available in analog land. It is not used in TRANSMISSION. as yet anyway, except for compressed (digitally reduced) satellite form such as athe Scientific Atlanta system. Which, if you move the camera diagionally, you will see large sections of the pictures (blocks) move in steps, not smoothly as in analog land. So there are still artifacts. 2. Digital recording relies on emense bnadwidth to accomodate 4,4,4 or 4,2,2, or 4,1,1 sampling and bit stream. Also some data compression schemes have such complex math to produce look ahead and fill frames that the cost is currently prohibitive. At the 1996 NAB, Zenith and Sony both stated that digital TV's in mass production would start at $3500. 3. I use digital at my TV station too. And not some cluge "digital" tape machine boxes, but dull digital, stays in the computer, no tape format of Avid, including the digital fiber link ATM switching. It goes from my cameras intothe computer, gets massaged in the computer and then transmitted into the air as an NTSC encoded signal. No one in the country is more digital than my station and even my news trucks are full digital. 4. Most of the top 40 ADI stations DO NOT use digital. Even the networks still use analog tape. There is some digital equipment in PRODUCTION/EDIT suites, but escept for those of us with Avid Airplay or similar devices, there is no DIGITAL on-line playback in mass quantities. So you are wrong there. Locally, Channel 2 (CBS) uses analog, 5 (NBC) uses MII analog, 7 (ABC) uses Betacart analog. 9, WGN) uses MII and is converting to beta tape. 11 (PBS) uses 1", and beta. 20 (PBS) uses 3/4" U-matic, 26 WCIU) uses 3/4" and some 1/2". 32 (FOX) uses Betacart, 38 uses Avid Airplay, and 3/4". 44 uses Airplay and beta /airplay for news, 50 uses 3/4", 56 uses 3/4", 60 uses 3/4" and beta, 62 uses 3/4", and 66 uses a Betacart. Only two DIGITAL out of 15 stations. 5. HBO and others who use digital on KU band for direct TV, are converting the signal from a received C band ANALOG signal. It is uplinked from HBO on Long Island, downlinked in Colorado, coonverted to compressed digital for Ku. There is no such think as lossless compression, 2:1 or 50:1 you always lose something. Read teh Snell and Wilcox book, or the Intelsat Digital Satellite book. 6. You are dead wrong on the build up of sidebands on analog NTSC. Unless you transmit a sweep signal, or white noise, the sidebands decrease at a rate of 30 db/MHz initially, and 15 dB/Mhz after that for any televised scene. Using a time lapse/storage scope, which shows a peak hold, you will always achieve a curve showing the distribution of the sideband energy. That curve is always decreasing with frequency. The digital spectrum is FLAT across the entire 6 MHz except for a spike for the pilot tone. So do you want to comp[ete with a sideband that is - 50dBc or continous noise at -12 dBc? 7. The only uncompressed thus lossless digital format is D1, which records in the 4, 4, 4 format. Considering that you cannot get a SINx/X pulse through it nearly as well as you can in an old 2" AVR-1 analog quad machine, I would say it still has loss! D2 is a composit ANALOG signal, digitized and bit reduced and is not a DIGITAL recording system. It does not take in 0's and 1's and spit out 0's and 1's, it takes in composit analog NTSC and spits out composoit analog NTSC. Go read up on your "digitized" recording formats. It is NOT digital because the box or name plate says it is digital. 8. NTSC is not "grainy" unless the source is grainy. Even 35 mm film has grain noise. So look. There is no difference in the S/N ratio of HDTV and NTSC at the source. In transmission the analog signal S/N ratio decreases with distance in a gradual manner. Transmission/reception standards are such that a "noiseless" picture is 60 dB S/N. There is noise there, it is not visible tothe naked eye. For video tape and Cable TV figures in the 40 dB-45 dB range are considered acceptable noise levels. At 30 dB there is noise which mnost people will see easily. The HDTV digital signal will have an increase in BER (bit error rate) which is masked by processing. Then the picture degrades to nothing in about 2 dB change of S/N ratio at the BER threshold. BER covers the noise, but subtracts from the accuracy of the picture in error correction porportional to the increase in BER. 9. Film is usually regarded as 2000 line resolution equivelent. Line doubling ( a common term in digital TV) is a cheap way of doubling the number of scan lines on the screen, thus making the individual lines harder to see because they optically blend together. The vertical scan rate is doubled and the same picture is presented twice in the same amount of time. It does not add resolution. With 525 (242.5) you can see individual scan lines and the bigger the screen, the bigger the space between the scan lines, so you fill in the spaces with duplicate lines. Because of aperature effect in the display device (CRT or whatever) and the optical limitation of your eyes, the scan lines blend together and "disapear". 10. Horizontal resolution is only slightly better in HDTV than NTSC because the scan line is longer. Thus each pixel must cover more real space (or time) in HDTV, or you must increase the number of pixels per line to compensate for the longer line. Since the screen (CRT) is the same width for HDTV and NTSC in TIME, the increased numnber of pixels per line simply compensates for the physically wider screen. 11. You cant put your digital equipment on a kite,m R/C plane, small boat, ultralight, car, plane or other portable/mobile operation without considerable vost in money, battery life or physical weight. Analog wins the weight/battery/size contest every time. It wins the $$ contest every time too. So go back to your books and read up on the differences between recording and transmission and between digitized alanog and DIGITAL. Then spout off when you have the right answers. So far you are batting zero. From ka1kjz@tigger.jvnc.net Fri Apr 19 19:52:48 1996 Received: from tigger.jvnc.net (tigger.jvnc.net [128.121.50.145]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id TAA14543 for ; Fri, 19 Apr 1996 19:52:39 -0500 (CDT) Received: from ka1kjz.jvnc.net by tigger.jvnc.net with SMTP id AA21159 (5.65c/IDA-1.4.4 for ss@tapr.org); Fri, 19 Apr 1996 20:52:24 -0400 Date: Fri, 19 Apr 1996 20:52:24 -0400 Message-Id: <199604200052.AA21159@tigger.jvnc.net> X-Sender: ka1kjz@tigger.jvnc.net X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: ss@tapr.org From: "Ronald C. Barnes" Subject: Re: File your comments in RM-8737! Cc: ss@tapr.org At 11:39 AM 4/19/96 -0500, ATVQ@aol.com wrote: >Shows what you dont know. I have been at every HDTV demo/test. So I think I >know a lot more about it than you. Also NAB is OVER, I was there too. >1. Digital is not "proven" as you claim. It is USED, because it offers some >things in RECORDING that are not available in analog land. It is not used in >TRANSMISSION. as yet anyway, except for compressed (digitally reduced) >satellite form such as athe Scientific Atlanta system. Which, if you move >the camera diagionally, you will see large sections of the pictures (blocks) >move in steps, not smoothly as in analog land. So there are still artifacts. > Repeat after me.... DIGITALLY COMPRESSED, MPEG-2 VIDEO IS USED ON A DAILY BASIS BY THE MAJOR BROADCASTERS FOR SATELLITE DISTRIBUTION. Perhaps you have heard the term.. "General Instruments Video Cipher II". >2. Digital recording relies on emense bnadwidth to accomodate 4,4,4 or >4,2,2, or 4,1,1 sampling and bit stream. Also some data compression schemes >have such complex math to produce look ahead and fill frames that the cost is >currently prohibitive. At the 1996 NAB, Zenith and Sony both stated that >digital TV's in mass production would start at $3500. > For now.... how much did the first color sets cost? You'll have to look at it as a percentage of per capita income, as the dollar was valued differently back then. I remember my parents saying, "only the rich had color TV in the 50's". >3. I use digital at my TV station too. And not some cluge "digital" tape >machine boxes, but dull digital, stays in the computer, no tape format of >Avid, including the digital fiber link ATM switching. It goes from my cameras >intothe computer, gets massaged in the computer and then transmitted into the >air as an NTSC encoded signal. No one in the country is more digital than my >station and even my news trucks are full digital. > Having an Avid does NOT constitute being fully digital. Perhaps you've seen in the trades the new Asia Broadcast Center in Singapore, a partnership of Group W and Yarra Films. Fully SDI, the only analog boxes are the Odetics TCS-90's, but they run DBETA with analog outs. We have 3 Avids, and two fully digital edit suites with embedded SDI audio. Beginning next month (once the switcher the boss bought at NAB arrives) construction of the fully digital studio will commence. So dont say no one is more digital than you. >4. Most of the top 40 ADI stations DO NOT use digital. Even the networks >still use analog tape. There is some digital equipment in PRODUCTION/EDIT >suites, but escept for those of us with Avid Airplay or similar devices, >there is no DIGITAL on-line playback in mass quantities. So you are wrong >there. Locally, Channel 2 (CBS) uses analog, 5 (NBC) uses MII analog, 7 >(ABC) uses Betacart analog. 9, WGN) uses MII and is converting to beta tape. > 11 (PBS) uses 1", and beta. 20 (PBS) uses 3/4" U-matic, 26 WCIU) uses 3/4" >and some 1/2". 32 (FOX) uses Betacart, 38 uses Avid Airplay, and 3/4". 44 >uses Airplay and beta /airplay for news, 50 uses 3/4", 56 uses 3/4", 60 uses >3/4" and beta, 62 uses 3/4", and 66 uses a Betacart. Only two DIGITAL out >of 15 stations. > I cant speak for Chicago, but NYC, Hartford/NewHaven, LA, and Boston, hell most of the stations have some sort of digital machines, either for editing, or on air playback. And, as I mentioned before, WWOR uses all DBETA in playback, WPIX uses all D-3 for on-air playback. And as for on online digital playback?!?!? Well, I must be hallucinating when I clean the DBETA machines in TLC, Speedvision and Outdoor Life. Also that Tektronix Profile in The History channel and on Continuous Hits 4 must be a figment of my imagination. At the VR disk recorder on Discovery West's delay must also be unnecessary. >5. HBO and others who use digital on KU band for direct TV, are converting >the signal from a received C band ANALOG signal. It is uplinked from HBO on >Long Island, downlinked in Colorado, coonverted to compressed digital for Ku. > There is no such think as lossless compression, 2:1 or 50:1 you always lose >something. Read teh Snell and Wilcox book, or the Intelsat Digital Satellite >book. > Repeat after me... ALL HBO SERVICES ARE DISTRIBUTED TO THE CABLE HEADEND AS DIGICIPHER II. I mean that, C band, 6 channels per transponder, all digital. Yes DirecTV does downlink it, from C-band, as DG-II, re-encodes it to thier subset of MPEG-II and re transmits it on the DBS band. If thats not true, and cable networks are still analog, I can throw away the two Digicipher boxes we have? I guess they arent needed. Speedvision and Outdoor Life are also on C-band as DG-II, Speed is uplinked by us, and OLC is uplinked by HBO on one of their spare DG-II channels, also on C-band. >6. You are dead wrong on the build up of sidebands on analog NTSC. Unless >you transmit a sweep signal, or white noise, the sidebands decrease at a rate >of 30 db/MHz initially, and 15 dB/Mhz after that for any televised scene. > Using a time lapse/storage scope, which shows a peak hold, you will always >achieve a curve showing the distribution of the sideband energy. That curve >is always decreasing with frequency. The digital spectrum is FLAT across >the entire 6 MHz except for a spike for the pilot tone. So do you want to >comp[ete with a sideband that is - 50dBc or continous noise at -12 dBc? > Who's competing with what here? SO WHAT IF IT LOOKS LIKE NOISE! The only people on HDTV channels will be HDTV broadcasters. Lets not go into NTSC to HDTV implementation periods and all that, when the dust settles, the only thing in the TV band will be TV stations, like it always has been, always will be, who cares WHAT it is. >7. The only uncompressed thus lossless digital format is D1, which records >in the 4, 4, 4 format. Considering that you cannot get a SINx/X pulse >through it nearly as well as you can in an old 2" AVR-1 analog quad machine, >I would say it still has loss! >D2 is a composit ANALOG signal, digitized and bit reduced and is not a >DIGITAL recording system. It does not take in 0's and 1's and spit out 0's >and 1's, it takes in composit analog NTSC and spits out composoit analog >NTSC. Go read up on your "digitized" recording formats. It is NOT digital >because the box or name plate says it is digital. > Uhhhhh, D1 is 4:2:2. I'll have to read the book on the D2's, but I KNOW FOR A FACT! That DBETA is fully digital, 4:2:2 component serial digital. You can split hairs and say that ANYTHING layed on a tape is analog, in the case of digital, either alot of something or nothing (1's and 0's). But... on the D2's, whats the parallel digital interface for? Decoration? In my experience with the Ampex 300's, the analog spigots were just that, to interface with the rest of the world. Everything else in the box is digital, even on tape. Just because it has an analog spigot on the back doesnt make it "not digital". >8. NTSC is not "grainy" unless the source is grainy. Even 35 mm film has >grain noise. So look. There is no difference in the S/N ratio of HDTV and >NTSC at the source. In transmission the analog signal S/N ratio decreases >with distance in a gradual manner. Transmission/reception standards are such >that a "noiseless" picture is 60 dB S/N. There is noise there, it is not >visible tothe naked eye. For video tape and Cable TV figures in the 40 >dB-45 dB range are considered acceptable noise levels. At 30 dB there is >noise which mnost people will see easily. The HDTV digital signal will have >an increase in BER (bit error rate) which is masked by processing. Then the >picture degrades to nothing in about 2 dB change of S/N ratio at the BER >threshold. BER covers the noise, but subtracts from the accuracy of the >picture in error correction porportional to the increase in BER. > In a consumer driven market such as television, do you really think that John and Jane Q Public really CARE about the s/n ratio and BER? They want to sit down and watch a perfect, noiseless picture that HDTV will provide, along with all the "extras" that have been figured into the standard. I'll take motion artifacts and concealment any day over 2 channels of really poor audio and a HORRIBLE picture. Yes NTSC is a terrible picture, I have to laugh at TV sets that use slot-mask tubes (ie Trinitron) to conceal the problems with the picture. A great thing about digital TV is the fact that it either works or it doesnt. >9. Film is usually regarded as 2000 line resolution equivelent. Line >doubling ( a common term in digital TV) is a cheap way of doubling the >number of scan lines on the screen, thus making the individual lines harder >to see because they optically blend together. The vertical scan rate is >doubled and the same picture is presented twice in the same amount of time. > It does not add resolution. With 525 (242.5) you can see individual scan >lines and the bigger the screen, the bigger the space between the scan lines, >so you fill in the spaces with duplicate lines. Because of aperature effect >in the display device (CRT or whatever) and the optical limitation of your >eyes, the scan lines blend together and "disapear". > See my rantings about slot-mask, about the same thing as what you describe. >10. Horizontal resolution is only slightly better in HDTV than NTSC because >the scan line is longer. Thus each pixel must cover more real space (or >time) in HDTV, or you must increase the number of pixels per line to >compensate for the longer line. Since the screen (CRT) is the same width for >HDTV and NTSC in TIME, the increased numnber of pixels per line simply >compensates for the physically wider screen. > Again, SO? >11. You cant put your digital equipment on a kite,m R/C plane, small boat, >ultralight, car, plane or other portable/mobile operation without >considerable vost in money, battery life or physical weight. Analog wins the >weight/battery/size contest every time. It wins the $$ contest every time >too. > For now. You couldnt do that (practically) with analog NTSC either until the late 80's. Yes, digital is big, bulky and expensive, for now. I really cant imagine John Q. Ham hanging a camera, transmitter, etc on a kite back in the 50's (or the 60's and 70's for that matter) when NTSC first came out. Granted the digital chipsets are kind of pricy, for now, $1500 for an MPEG-2 encoder, and around $100 for a decoder. The encoders are more expensive probably because they dont sell too many of them, YET. And, have you seen the DVC-pro gear from Sony and Panasonic? About the same size as my 8mm Sony Handycam. So, give it time, digital will become practical very shortly. I imagine there were similar discussions in 1953 when we were about to go from monochrome to NTSC color. I'm sure similarly short minded engineers thought it would be the death of television itself. But if it werent for color, we wouldnt have jobs, as a monochrome signal can be maintained by just about anyone. And that I think is the root cause of the HDTV / Digital video debate. A digital signal can be spec'd, installed, maintained and measured by anyone. Just hook it up and go. (dont even think of going off about crimped cables). And yes, our jobs are also threatened by the complexity of digital. Things are rapidly becoming a "black box" technology. No more component level troubleshooting, just replace the board, and any monkey can do that. But the same can be said of automobiles, they too are becoming black box. How many backyard mechanics are comfortable inside their nice new 1996 fuel injected, airbagged, ABS equipped wonder buggies! Yes digital TV / HDTV will kill off the engineer with the garage mechanic mentality, leaving only the best and brightest ones who kept up with the everchanging technology and embraced it as it arrived. >So go back to your books and read up on the differences between recording and >transmission and between digitized alanog and DIGITAL. Then spout off when >you have the right answers. So far you are batting zero. > Well I do have the right answers. I work for TWELVE major cable networks, with full post production, marketing and sales support. Look it up in the book, Group W Network Services, and check the trade publications, there's usually an article or two about us in each issue. -- *********************************************************************** ** Ronald C. Barnes KA1KJZ Engineering Tech, Group W Satellite ** ** 1591 W. Broad Street ARRL CT Section Technical Coord. ** ** Stratford, CT 06497 Member, Soc. Broadcast Engineers ** ** ** ** The preceding are my opinions, mine, mine, mine! ** ** Any attempt to say otherwise will result in a hearty laugh ** *********************************************************************** From wd5ivd@tapr.org Fri Apr 19 21:18:35 1996 Received: (from wd5ivd@localhost) by tapr.org (8.7.5/8.7.3/1.9) id VAA17143 for ss@tapr.org; Fri, 19 Apr 1996 21:18:35 -0500 (CDT) From: Greg Jones Message-Id: <199604200218.VAA17143@tapr.org> Subject: Re: [SS:219] Re: File your comments in RM-8737! To: ss@tapr.org Date: Fri, 19 Apr 1996 21:18:34 -0500 (CDT) In-Reply-To: <199604200052.AA21159@tigger.jvnc.net> from "Ronald C. Barnes" at Apr 19, 96 08:03:01 pm X-Mailer: ELM [version 2.4 PL25] Content-Type: text All very interesting reading about NTSC and HDTV stuff. However -- we seem to have left the SS topic flow that was at the beginning. Bandwidth is bandwidth. If we can provide something that pumps a lot of bits and does not interfer with exsiting services, then I think we will find a lot of things that people we want to run over it that we can't think of now. Cheers - Greg, WD5IVD From JRA1854@tntech.edu Fri Apr 19 22:06:08 1996 Received: from tntech.edu (gemini.tntech.edu [149.149.11.7]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id WAA18828 for ; Fri, 19 Apr 1996 22:06:06 -0500 (CDT) Received: from tntech.edu by tntech.edu (PMDF V5.0-7 #11446) id <01I3QP3RYQTCQULNHS@tntech.edu> for ss@tapr.org; Fri, 19 Apr 1996 22:05:27 -0500 (CDT) Date: Fri, 19 Apr 1996 22:05:27 -0500 (CDT) From: Jeffrey Austen Subject: Re: [SS:219] Re: File your comments in RM-8737! To: ss@tapr.org Message-id: <01I3QP3RZ0GYQULNHS@tntech.edu> X-VMS-To: IN%"ss@tapr.org" MIME-version: 1.0 Content-type: TEXT/PLAIN; CHARSET=US-ASCII Content-transfer-encoding: 7BIT > >Shows what you dont know. I have been at every HDTV demo/test. So I think I [cut] > Repeat after me.... DIGITALLY COMPRESSED, MPEG-2 VIDEO IS USED ON A DAILY [cut] How does this relate to Spread-Spectrum? Jeff, k9ja From c-three@telepost.no Sat Apr 20 03:18:26 1996 Received: from netto.telepost.no (netto.telepost.no [193.212.1.11]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id DAA06748 for ; Sat, 20 Apr 1996 03:18:23 -0500 (CDT) Received: from c-three.telepost.no by netto.telepost.no with SMTP (8.6.13/nms1.1) id for ; Sat, 20 Apr 1996 10:18:17 +0200 Message-Id: <199604200818.12310.telepost.no@telepost.no> X-Sender: c-three@telepost.no X-Mailer: Windows Eudora Pro Version 2.1.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Sat, 20 Apr 1996 10:18:17 +0200 To: ss@tapr.org From: Per-Tore Aasestrand Subject: Re: SS for position At 15:20 19.04.96 BST, Sean wrote: >Hello Per-Tore, > >Thanks for you original lead I am moving forward at last. >Do you know of any applications where this degree of timing resolution >has been used ? Yes! I would look closely to developments at the Lawrence Livermore National Laboratory with respect to what they call "Micropower Impulse Radar" (MIR). This is one of the more interesting new approaches I've seen in a long time. The results they've demonstrated are just amazing (for me at least)! There is a lot of information on this available on their web-site. Go to http://www.llnl.gov, and look for MIR. You will even find references to several applications that are in some way related to your own. >I thought spread spectrum systems were less subject to multipath because >the reflected signal is delayed compared with the direct signal path and >it is treated as any other uncorrelated input. The higher the chip rate >the smaller the multipath problem. I think this is basically correct. MIR is, in my opinion, just another form of SS modulation. They send a stream of narrow pulses with a high PRF. The PRF is in turn modulated by some sort of Gaussian noise. The emission bandwidth can be very high. >I still do not know where to start in trying to build a test system. Do >you know of any articles on test projects ? Good luck with your project, and keep me posted on your advances! Regards, Per-Tore LA7NO ----------------------------------+-------------------------------- | Per-Tore Aasestrand | E-mail : c-three@telepost.no | | C-Three Systems AS | Fax : + 47 - 55 23 18 88 | | P.O. Box 1708 | Voice : + 47 - 55 32 67 67 | | N-5024 Bergen, Norway | Mobile : + 47 - 92 04 44 76 | ----------------------------------+-------------------------------- From djk@dirku.demon.co.uk Sat Apr 20 07:27:39 1996 Received: from dirku.demon.co.uk (dirku.demon.co.uk [158.152.30.189]) by tapr.org (8.7.5/8.7.3/1.9) with ESMTP id HAA12655 for ; Sat, 20 Apr 1996 07:27:23 -0500 (CDT) Received: (from djk@localhost) by dirku.demon.co.uk (8.7.1/8.7.1) id MAA08526; Sat, 20 Apr 1996 12:39:32 +0100 Date: Sat, 20 Apr 1996 12:39:32 +0100 (BST) From: Dirk-Jan Koopman X-Sender: djk@dirku.demon.co.uk Reply-To: djk@dirku.demon.co.uk To: ss@tapr.org Subject: Re: [SS:219] Re: File your comments in RM-8737! In-Reply-To: <199604200052.AA21159@tigger.jvnc.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII On Fri, 19 Apr 1996, Ronald C. Barnes wrote: > At 11:39 AM 4/19/96 -0500, ATVQ@aol.com wrote: > >Shows what you dont know. I have been at every HDTV demo/test. So I think I > >know a lot more about it than you. Also NAB is OVER, I was there too. > >1. Digital is not "proven" as you claim. It is USED, because it offers some > >things in RECORDING that are not available in analog land. It is not used in > >TRANSMISSION. as yet anyway, except for compressed (digitally reduced) > >satellite form such as athe Scientific Atlanta system. Which, if you move > >the camera diagionally, you will see large sections of the pictures (blocks) > >move in steps, not smoothly as in analog land. So there are still artifacts. > > > > Repeat after me.... DIGITALLY COMPRESSED, MPEG-2 VIDEO IS USED ON A DAILY > BASIS BY THE MAJOR BROADCASTERS FOR SATELLITE DISTRIBUTION. Perhaps you > have heard the term.. "General Instruments Video Cipher II". > etc... This discussion is quite interesting, but perhaps you could continue it elsewhere - please. From ka1kjz@tigger.jvnc.net Sat Apr 20 15:38:26 1996 Received: from tigger.jvnc.net (tigger.jvnc.net [128.121.50.145]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id PAA28502 for ; Sat, 20 Apr 1996 15:38:23 -0500 (CDT) Received: from ka1kjz.jvnc.net by tigger.jvnc.net with SMTP id AA16712 (5.65c/IDA-1.4.4 for ss@tapr.org); Sat, 20 Apr 1996 16:38:18 -0400 Date: Sat, 20 Apr 1996 16:38:18 -0400 Message-Id: <199604202038.AA16712@tigger.jvnc.net> X-Sender: ka1kjz@tigger.jvnc.net X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: ss@tapr.org From: "Ronald C. Barnes" Subject: Re: File your comments in RM-8737! Cc: ss@tapr.org At 10:16 PM 4/19/96 -0500, Jeffrey Austen wrote: >> >Shows what you dont know. I have been at every HDTV demo/test. So I think I >[cut] >> Repeat after me.... DIGITALLY COMPRESSED, MPEG-2 VIDEO IS USED ON A DAILY >[cut] > >How does this relate to Spread-Spectrum? > >Jeff, k9ja > You're right, absolutely nothing. But the question begs to be asked however, what does filing comments on the FCC RM for HTDV have to do with it too? At least you got some entertainment for an otherwise slow list. Ron :) -- *********************************************************************** ** Ronald C. Barnes KA1KJZ Engineering Tech, Group W Satellite ** ** 1591 W. Broad Street ARRL CT Section Technical Coord. ** ** Stratford, CT 06497 Member, Soc. Broadcast Engineers ** ** ** ** The preceding are my opinions, mine, mine, mine! ** ** Any attempt to say otherwise will result in a hearty laugh ** *********************************************************************** From ka1kjz@tigger.jvnc.net Sat Apr 20 15:38:31 1996 Received: from tigger.jvnc.net (tigger.jvnc.net [128.121.50.145]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id PAA28525 for ; Sat, 20 Apr 1996 15:38:26 -0500 (CDT) Received: from ka1kjz.jvnc.net by tigger.jvnc.net with SMTP id AA16717 (5.65c/IDA-1.4.4 for SS@TAPR.ORG); Sat, 20 Apr 1996 16:38:21 -0400 Date: Sat, 20 Apr 1996 16:38:21 -0400 Message-Id: <199604202038.AA16717@tigger.jvnc.net> X-Sender: ka1kjz@tigger.jvnc.net X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: SS@tapr.org From: "Ronald C. Barnes" Subject: Spread Spectrum Chipset Hello pholx... I was poking aroung on the Maxim Semiconductor web site yesterday and came across this little gem... MAX2402 800MHZ to 1000MHz Transmitter ----------------------------- The MAX2402 transmitter integrates a double-balanced mixer, buffered local oscillator (LO) port, variable gain stage, and power amplifier into a single IC. It is intend-ed for use in the 800MHz to 1000MHz band, and is compatible with both direct-sequence and frequency-hopping spread-spectrum designs in the 902MHz to 928MHz ISM band. In a typical application, a digital baseband signal is mixed with a local oscillator signal to yield a BPSK-modulated carrier at the antenna. Alternatively, the baseband input may be grounded and an FSK-modu-lated LO signal applied directly to the LO port. The LO port consists of a limiting amplifier that can accept a single-ended or differential signal with input power between -6dBm and +6dBm in the frequency range of 800MHz to 1000MHz. The baseband modulation input is linear over a 2V range, and limits with larger signal levels within the supply range. The double-balanced mixer has been optimized for high carrier rejection. The variable gain stage offers typically 40dB of adjustment range. The power amplifier provides more than 20dBm output power and has a bias adjustment, which allows adjustment of efficiency and harmonic distortion. A shutdown function reduces the current draw to less than 2=B5A in less than 10=B5s. The MAX2402 comes in a 20-pin SSOP package to minimize board area. APPLICATIONS ------------- Direct-Sequence Spread-Spectrum Transmitter Frequency-Hopping Spread-Spectrum Transmitter FSK, GMSK, BPSK, and ASK Digital Transmitter AM and FM Analog Transmitter =A9 Low-Cost, Flexible Transmitter FEATURES: --------- More than 100mW of Output Power into 50=BD Operates from 800MHz to 1000MHz Single +5V Supply 20-Pin SSOP Package Uses Less than 2=B5A in Power-Down More than 35dB of Power Adjustment Range LO Input Power Range from -6dBm to +6dBm 2V Linear Range on Modulation Input I dont have pricing or availability, but I will pass that along to y'all after I talk to them Monday. Looks interesting. Ron :) -- *********************************************************************** ** Ronald C. Barnes KA1KJZ Engineering Tech, Group W Satellite ** ** 1591 W. Broad Street ARRL CT Section Technical Coord. ** ** Stratford, CT 06497 Member, Soc. Broadcast Engineers ** ** ** ** The preceding are my opinions, mine, mine, mine! ** ** Any attempt to say otherwise will result in a hearty laugh ** *********************************************************************** From 103130.1467@CompuServe.COM Sat Apr 20 17:17:22 1996 Received: from dub-img-2.compuserve.com (dub-img-2.compuserve.com [198.4.9.2]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id RAA02738 for ; Sat, 20 Apr 1996 17:17:19 -0500 (CDT) Received: by dub-img-2.compuserve.com (8.6.10/5.950515) id SAA16493; Sat, 20 Apr 1996 18:17:03 -0400 Date: 20 Apr 96 18:15:42 EDT From: RICARDO DENIS <103130.1467@CompuServe.COM> To: all Subject: TCM Message-ID: <960420221541_103130.1467_JHG117-1@CompuServe.COM> Hello All, My name is Rick (HR2KOS) and I live in Honduras. I'm interested in any and all areas of amateur radio that are at the forefront of technology, even if i don't understand them completely. SS is certainly one of them so I decided to learn more by joining this discussion group (and TAPR soon). The other day I bought a new modem for my computer and in the manual it says that it uses "Tellis Code Modulation". Can anyone tell this layman (layham) what "TCM" is or how it works, and if it can be applied to ham radio? Maybe you could suggest a book. Any replies/info are deeply appreciated. tnx 73, Rick HR2KOS From bm@lynx.ve3jf.ampr.org Sat Apr 20 23:46:25 1996 Received: from lynx.ve3jf.ampr.org (lynx.ve3jf.ampr.org [44.135.96.100]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id XAA18557 for ; Sat, 20 Apr 1996 23:46:17 -0500 (CDT) Received: (from bm@localhost) by lynx.ve3jf.ampr.org (8.6.12/8.6.12) id EAA00530 for ss@tapr.org; Sun, 21 Apr 1996 04:45:57 GMT From: Barry McLarnon VE3JF Message-Id: <199604210445.EAA00530@lynx.ve3jf.ampr.org> Subject: Re: [SS:221] Re: File your comments in RM-8737! To: ss@tapr.org Date: Sun, 21 Apr 1996 04:45:56 +0000 (GMT) In-Reply-To: <01I3QP3RZ0GYQULNHS@tntech.edu> from "Jeffrey Austen" at Apr 19, 96 10:16:35 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text > How does this relate to Spread-Spectrum? I agree that this isn't the place for a lengthy debate on the merits of analog vs digital TV, but before this little tangent draws to a close, I'd like to toss in some comments that do relate to spread spectrum. Henry claims that conversion from analog to digital TV would be enormously expensive - for one thing, receivers cost something like $3500. He's right, no doubt... but only in the context of professional broadcasting. Let's try and look at a more relevant context: transmission of digital video by radio amateurs. He equates digital video with HDTV, and then uses that to show that it would be far too expensive for amateurs to convert from analog TV to digital. This is somewhat analogous to saying that it would be impractical to convert from horse and buggies to automobiles because Ferraris are too expensive. HDTV is at the extreme end of a wide range of digital video techniques that range all the way down to videoconferencing systems which can do a passable job of transmitting full-motion video at landline and medium-speed packet bit rates (19.2-56 kbps). Obviously, you trade off quality (resolution, frame rate, color depth, etc) to get to the low end, but the fact remains that remarkably useful video links can be set up which use two orders of magnitude less bandwidth than an NTSC signal. And quality improves rapidly as you increase the bit rate. Hams are supposed to be communicators, not broadcasters. They do not need to follow the practices of the broadcast industry. Radio broadcasters still use AM, but despite AM's superior audio quality, hams (except for a few diehards) have switched to SSB, since it's a more efficient and robust method to transmit voice signals. I think a similar transition should be taking place from NTSC TV to digital video in the ham bands. Consider the fact that a single ATV user transmitting in the 70cm band is monopolizing 30% of a prime band (in Canada, or parts of the US, where only 430-450 MHz is available), using a modulation technique which is more than half a century old, and which is totally intolerant of spectrum sharing. Consider how many users could be transmitting digital video at say 56 kbps in that bandwidth, using either narrowband packet or spread spectrum (using CDMA and the superior spectrum reuse properties of digital signalling). Consider the ease with which those users could internetwork over long distances via a variety of media. You get the picture (pun intended!)... I seriously doubt whether many amateur video applications require broadcast-quality video - again, we're not broadcasters! The main reason that analog video continues to prevail on the ham bands has to be cost - NTSC equipment is ubiquitous and relatively inexpensive. I think a couple of things have to happen to kickstart the transition to digital: 1) The ATV folks have to break away from the notion that video has to be equivalent in quality to broadcast NTSC for them to do their thing (whatever that is), and to start to appreciate the advantages of digital video transmission. 2) Packet systems operating at 56 kbps and up have to become more available and affordable. 56k is still on the rise, but the real promise for bit rates of this order and more is in spread spectrum. You could do impressive digital video with some of the ISM band SS modems, but we really need a homegrown amateur SS modem that's cheaper and has more processing gain than most of the ISM stuff. As for other digital video equipment, most hams already have PCs with monitors which are superior to NTSC resolution, and with combination camera/video capture devices under $100 at the low end, this stuff is becoming more affordable all the time. I'll grant that digital video isn't going to take over applications like balloon-launched ATV anytime soon, but it should start making inroads in other areas, and the sooner, the better. Not trying to be argumentative, just stating my humble opinion... Barry -- Barry McLarnon VE3JF/VA3TCP | Internet: bm@hydra.carleton.ca Ottawa Amateur Radio Club | AMPRnet: bm@lynx.ve3jf.ampr.org Packet Working Group | Web: http://hydra.carleton.ca From daves@aquasoft.com.au Sun Apr 21 01:56:58 1996 Received: from aqua.aquasoft.com.au (root@[192.245.14.1]) by tapr.org (8.7.5/8.7.3/1.9) with SMTP id BAA27278 for ; Sun, 21 Apr 1996 01:56:52 -0500 (CDT) Received: from syd-ts1-214.tpgi.com.au (syd-ts1-214.tpgi.com.au [203.12.160.214]) by aqua.aquasoft.com.au (8.6.12/8.6.12) with SMTP id QAA28342 for ; Sun, 21 Apr 1996 16:52:28 +1000 Received: by syd-ts1-214.tpgi.com.au with Microsoft Mail id <01BB2FA3.2D7D9440@syd-ts1-214.tpgi.com.au>; Sun, 21 Apr 1996 16:54:17 +-1000 Message-ID: <01BB2FA3.2D7D9440@syd-ts1-214.tpgi.com.au> From: David Stirrup To: "ss@tapr.org" Subject: RE: 218] Re: File your comments in RM-8737! Date: Sun, 21 Apr 1996 16:50:52 +-1000 Encoding: 162 TEXT Can someone please help my confusion, I have been following this thread a while and I am trying to determine it's relevance to Spread Spectrum and not ATV. Is it that I have missed the beginning message?? I take it that the intended original issue was the bandwidth requirements to transmit digital video using SS techniques. I expect that I also missed the part about how you can have many simultaneous transmissions using the same bandwidth but on a different PN sequence. How analog became involved in a digital only mode discussion I am puzzled by. Please help illuminate my ignorance. I am sure there are others who share my confusion. Dave Stirrup VK2XDS ---------- From: ATVQ@aol.com[SMTP:ATVQ@aol.com] Sent: Friday, 19 April 1996 21:39 To: ss@tapr.org Subject: [SS:218] Re: File your comments in RM-8737! Shows what you dont know. I have been at every HDTV demo/test. So I think I know a lot more about it than you. Also NAB is OVER, I was there too. 1. Digital is not "proven" as you claim. It is USED, because it offers some things in RECORDING that are not available in analog land. It is not used in TRANSMISSION. as yet anyway, except for compressed (digitally reduced) satellite form such as athe Scientific Atlanta system. Which, if you move the camera diagionally, you will see large sections of the pictures (blocks) move in steps, not smoothly as in analog land. So there are still artifacts. 2. Digital recording relies on emense bnadwidth to accomodate 4,4,4 or 4,2,2, or 4,1,1 sampling and bit stream. Also some data compression schemes have such complex math to produce look ahead and fill frames that the cost is currently prohibitive. At the 1996 NAB, Zenith and Sony both stated that digital TV's in mass production would start at $3500. 3. I use digital at my TV station too. And not some cluge "digital" tape machine boxes, but dull digital, stays in the computer, no tape format of Avid, including the digital fiber link ATM switching. It goes from my cameras intothe computer, gets massaged in the computer and then transmitted into the air as an NTSC encoded signal. No one in the country is more digital than my station and even my news trucks are full digital. 4. Most of the top 40 ADI stations DO NOT use digital. Even the networks still use analog tape. There is some digital equipment in PRODUCTION/EDIT suites, but escept for those of us with Avid Airplay or similar devices, there is no DIGITAL on-line playback in mass quantities. So you are wrong there. Locally, Channel 2 (CBS) uses analog, 5 (NBC) uses MII analog, 7 (ABC) uses Betacart analog. 9, WGN) uses MII and is converting to beta tape. 11 (PBS) uses 1", and beta. 20 (PBS) uses 3/4" U-matic, 26 WCIU) uses 3/4" and some 1/2". 32 (FOX) uses Betacart, 38 uses Avid Airplay, and 3/4". 44 uses Airplay and beta /airplay for news, 50 uses 3/4", 56 uses 3/4", 60 uses 3/4" and beta, 62 uses 3/4", and 66 uses a Betacart. Only two DIGITAL out of 15 stations. 5. HBO and others who use digital on KU band for direct TV, are converting the signal from a received C band ANALOG signal. It is uplinked from HBO on Long Island, downlinked in Colorado, coonverted to compressed digital for Ku. There is no such think as lossless compression, 2:1 or 50:1 you always lose something. Read teh Snell and Wilcox book, or the Intelsat Digital Satellite book. 6. You are dead wrong on the build up of sidebands on analog NTSC. Unless you transmit a sweep signal, or white noise, the sidebands decrease at a rate of 30 db/MHz initially, and 15 dB/Mhz after that for any televised scene. Using a time lapse/storage scope, which shows a peak hold, you will always achieve a curve showing the distribution of the sideband energy. That curve is always decreasing with frequency. The digital spectrum is FLAT across the entire 6 MHz except for a spike for the pilot tone. So do you want to comp[ete with a sideband that is - 50dBc or continous noise at -12 dBc? 7. The only uncompressed thus lossless digital format is D1, which records in the 4, 4, 4 format. Considering that you cannot get a SINx/X pulse through it nearly as well as you can in an old 2" AVR-1 analog quad machine, I would say it still has loss! D2 is a composit ANALOG signal, digitized and bit reduced and is not a DIGITAL recording system. It does not take in 0's and 1's and spit out 0's and 1's, it takes in composit analog NTSC and spits out composoit analog NTSC. Go read up on your "digitized" recording formats. It is NOT digital because the box or name plate says it is digital. 8. NTSC is not "grainy" unless the source is grainy. Even 35 mm film has grain noise. So look. There is no difference in the S/N ratio of HDTV and NTSC at the source. In transmission the analog signal S/N ratio decreases with distance in a gradual manner. Transmission/reception standards are such that a "noiseless" picture is 60 dB S/N. There is noise there, it is not visible tothe naked eye. For video tape and Cable TV figures in the 40 dB-45 dB range are considered acceptable noise levels. At 30 dB there is noise which mnost people will see easily. The HDTV digital signal will have an increase in BER (bit error rate) which is masked by processing. Then the picture degrades to nothing in about 2 dB change of S/N ratio at the BER threshold. BER covers the noise, but subtracts from the accuracy of the picture in error correction porportional to the increase in BER. 9. Film is usually regarded as 2000 line resolution equivelent. Line doubling ( a common term in digital TV) is a cheap way of doubling the number of scan lines on the screen, thus making the individual lines harder to see because they optically blend together. The vertical scan rate is doubled and the same picture is presented twice in the same amount of time. It does not add resolution. With 525 (242.5) you can see individual scan lines and the bigger the screen, the bigger the space between the scan lines, so you fill in the spaces with duplicate lines. Because of aperature effect in the display device (CRT or whatever) and the optical limitation of your eyes, the scan lines blend together and "disapear". 10. Horizontal resolution is only slightly better in HDTV than NTSC because the scan line is longer. Thus each pixel must cover more real space (or time) in HDTV, or you must increase the number of pixels per line to compensate for the longer line. Since the screen (CRT) is the same width for HDTV and NTSC in TIME, the increased numnber of pixels per line simply compensates for the physically wider screen. 11. You cant put your digital equipment on a kite,m R/C plane, small boat, ultralight, car, plane or other portable/mobile operation without considerable vost in money, battery life or physical weight. Analog wins the weight/battery/size contest every time. It wins the $$ contest every time too. So go back to your books and read up on the differences between recording and transmission and between digitized alanog and DIGITAL. Then spout off when you have the right answers. So far you are batting zero.