++++++++++++++++++ See also K2 KK7P KDSP2 Info ++++++++++++++++++ From: "Eddy Avila" To: elecraft at mailman.qth.net Date: Wed, 07 May 2003 18:16:25 +0000 Subject: [Elecraft] Trade-in's? So, is Elecraft taking trade-in's on the new DSP board? http://elecraft.com/KDSP2/kdsp2.htm Well....thought I ask anyway! :) ++++++++++++++++++ Date: Wed, 07 May 2003 12:22:40 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: Elecraft List , QRP-L Subject: [Elecraft] New KDSP2 Advanced DSP Filter for the K2 We've just released the KDSP2 advanced DSP for the K2. Below is the KDSP2 product description. (We have also just released three transverters (6M, 2M and 220 MHz) that work with most HF rigs and an external band decoder box for controlling antenna switches and band pass filter boxes. Instead of putting everything in one huge email I'll be posting them separately to the list.) 73, Eric WA6HHQ http://www.elecraft.com ============ The Elecraft KDSP2 brings versatile, high-performance digital signal processing (DSP) technology to the K2 and K2/100 transceivers. The KDSP2 unit, which is fully integrated with the K2, plugs directly into the Control board. It's also very easy to assemble, with no surface mount components to install. The DSP IC and related parts are pre-installed on a small plug-in module. The KDSP2 provides up to four user-configurable filters in each mode (CW/SSB/data), complementing the K2's variable-bandwidth crystal filter. CW filter settings include center frequency and bandwidth, with "hard" and "soft" filter algorithms and bandwidths as narrow as 50 Hz. SSB filters provide programmable low and high cutoff frequencies. Four levels of noise reduction are available in CW and SSB modes, while SSB mode includes an automatic notch filter. The KDSP2 is unique in that noise reduction and auto notch parameters can be modified to suit the operator. Filter modes and features can be quickly accessed via the K2's DISPLAY button, while parameters adjustment is accomplished using the DSP module's own menu system. In addition, the unit's firmware is flash-based and field upgradeable. The DSP code is open-source to encourage community involvement and education. Like our KAF2 analog audio filter module, the KDSP2 includes a real time clock/calendar with its own backup battery. This feature is especially useful during field operation, eliminating the need for a separate clock for logging or contest use. Current drain of the KDSP2 can be reduced to approximately 10 mA by placing the audio filter subsystem in bypass mode. The DSP code for the KDSP2 is open source, allowing advanced users to create their own DSP features for the K2. User supplied alternate DSP code will be posted in a special KDSP2 download page on the Elecraft web page. (DSP source code and K2 interface link module will be placed on this web site by 6/30/03.) The KDSP2 is priced at $219. Additional information, pictures and orders can be placed via our web page at http://www.elecraft.com . KDSP2 units will be introduced and limited quantities will be available at the Dayton Hamvention, May 16 – 18th (Booth 196-7). Orders placed via our web page will begin shipping within two weeks following Dayton. ++++++++++++++++++ Date: Wed, 07 May 2003 13:18:30 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: Steve Hall Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] New KDSP2 Advanced DSP Filter for the K2 The flash chips are socketed on the KDSP2 and can be reprogrammed by the user, if they have a programmer, or sent back to us for reprogramming. Unfortunately there wasn't enough code space to add in-circuit reprogramming via the serial port at this time. 73, Eric Steve Hall wrote: > > How does one upgrade the DSP flash? Is there a connection header to > load the DSP code directly to the board or will it be programmed using > the KIO2? > > 73, > > Steve - W8HF > K1 #1520 > > > Eric wrote: > "In addition, the unit's firmware is flash-based and field upgradeable." > ++++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] New KDSP2 Advanced DSP Filter for the K2 Date: Wed, 7 May 2003 13:30:02 -0700 > Does this take the place of my Audio Filter option for the K2? Yes, it installs in your K2 in the same location, and in the same manner, as the KAF2. -Lyle +++++++++++++++++ Date: Wed, 07 May 2003 13:34:41 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: James1787 at aol.com Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] New KDSP2 Advanced DSP Filter for the K2 Yes, they plug in to the same socket on the control board. They can also be swapped back and forth as desired. 73, Eric James1787 at aol.com wrote: > Does this take the place of my Audio Filter option for the K2? > +++++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] DSP - 4 questions Date: Wed, 7 May 2003 15:13:01 -0700 Hello Tim! >... Here is what I would like to know: > > 1 - How much noise will I notice if I add the DSP unit? I am not sure what sort of noise you mean. The DSP noise reduction will significantly reduce thermal, hissy, background band noise. The DSP filters will sharpen your audio response, so you will hear less noise outside the desired passband. The DSP notch filter will reduce interference (noise) from heterodynes, like other stations tuning up nearby, etc. I have not heard, and no Field Tester has reported, any increase in background noise in the K2 receiver. So, I guess the best answer I can give you is: the DSP doesn't add noticeable noise, and sure helps get rid of the noise you want to eliminate! > 2 - Cab the DSP unit be disengaged at will so any DSP noise is > not constantly present. Again, there is no 'DSP" noise that has been reported. But, you can place it in "bypass" mode which puts the DSP chip to sleep, and turns off the analog-to-digital and digital-to-analog converters, so the unit acts as if it weren't present. Power consumption drops to about 10 mA in this mode. > 3 - If I am mainly a cw op, is the KAF2 a better choice than the DSP unit? Many of the testers are CW ops as well. Some of them report really liking how the noise reduction lets them open up the bandwidth to hear what's going on around them, without increasing the noise. And the CW audio filters are useful, too, with both "hard" and "soft" slope characteristics. The DSP is not perfect, of course, and there may be circumstances where you might prefer bypassing it, or using an analog filter like the KAF2. With the tremendous level of customization available, I suspect you would be happy with the KDSP2. 73, Lyle KK7P ++++++++++++++++++ Date: Wed, 07 May 2003 15:44:13 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: tlogan7 at cox.net Cc: Elecraft at mailman.qth.net Subject: Re: [Elecraft] DSP - 4 questions Hi Tim, We can't afford to take back all the potentially unbuilt KAF2s out there, but we will certainly take back unopened KAF2s bought from us in the past two weeks (after 4/23/03). If the KAF2 has been opened in any way we will not be able to accept it back since that would require us to totally inventory the kit. Also of interest - many customers have told us they want to have both :^). 73, Eric WA6HHQ tlogan7 at cox.net wrote: > What is the answer regarding trade-ins/returns/credit for new unbuilt > KAF2's that were purchased prior to knowing about the DSP unit? > Thanks for any help on the above. > 73/Tim +++++++++++++++++++ Date: Wed, 07 May 2003 16:45:36 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: Russell Boutell Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] KDSP2 and KNB2 together Both the KNB2 analog noise blanker and the noise reduction filter in the KDSP2 work very well together. The KNB2 is optimized for pulse type noise (from power lines, cars, electric fences etc.) and does an excellent job of blanking it before it can get further into the IF chain and cause ringing in the crystal filters. The KDSP2 noise reduction does a great job on broad band noise like background static and hiss, significantly reducing listening fatigue. 73, Eric WA6HHQ Russell Boutell wrote: > Hello, > > I was wondering if the esteemed field testers tried combinations of the > noise reduction filtering in the DSP with the analog noise blanker. I > wasn't sure if the combination would play together well or if that might > be too much signal manipulation. If it's better to use one or the other, > then I would think the analog noise blanker might still be the preferred > method for some repetitive noise, allowing the DSP to concentrate on > bandpass, auto-notching etc.. Any thoughts? > > 73, Russ W9EL (with KDSP2 on order :) +++++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] KDSP2 and KNB2 together Date: Wed, 7 May 2003 16:47:36 -0700 Hello Russ! > I was wondering if the esteemed field testers tried combinations of the > noise reduction filtering in the DSP with the analog noise > blanker... I wasn't > sure if the combination would play together well or if that might be too > much signal manipulation. These are for two very different types of noise, and the combination of DSP and the KNB2 is very, very powerful. The DSP has no observed adverse effect on the noise blanker. The noise blanker has no observed adverse effect on the KDSP2. 73, Lyle KK7P +++++++++++++++++++ Date: Wed, 07 May 2003 19:49:37 -0700 From: Wayne Burdick Organization: Elecraft To: k4wtf at enterzone.net Cc: elecraft at mailman.qth.net Subject: [Elecraft] Re: New KDSP2 Advanced DSP Filter for the K2 k4wtf at enterzone.net wrote: > > Is there a firmware upgradde (for the K2) required to make > use of the KDSP2? Hi John, Any revision that works with the KAF2 will work with the KDSP2 (2.01 or later). 73, Wayne N6KR ++++++++++++++++++ Date: Thu, 08 May 2003 01:07:28 -0400 From: Dale Boresz To: elecraft at mailman.qth.net Subject: Re: [Elecraft] DSP - 4 questions & a LONG answer Vic Rosenthal wrote: > Lyle Johnson wrote: > >> Many of the testers are CW ops as well. Some of them report really >> liking >> how the noise reduction lets them open up the bandwidth to hear >> what's going >> on around them, without increasing the noise. And the CW audio >> filters are >> useful, too, with both "hard" and "soft" slope characteristics. > > > > I would REALLY like to read some 'reviews' from the field testers, > particularly regarding CW performance. I have never found a DSP unit > that has the ability to change an unreadable weak signal in noise to a > readable one, but considering the source of this one -- maybe this is > it. How about some impressions? Vic, I am very fortunate to have been one of the field testers of the KDSP2, and as a CW op myself (for the past 38 years), I'd like to offer my impressions of the KDSP2. First, I should say that I have been a huge fan of the KAF2 audio filter, and if you review the archives, you'll find a number of postings that I have made in response to folks questioning whether or not the KAF2 was a worthwhile addition. I've found it to be extremely helpful in extracting weak CW signals from QRM, QRN or both. It does so by passing the audio signal through a relatively high-Q filter with a peaking response, which tends to discriminate against all other signals except for those within it's very narrow passband. The result is that noise is reduced, and of course QRM is also reduced. The KDSP2 achieves much the same effect but in a different way, and it does so with, in my opinion, a distinct advantage over the KAF2: the noise reduction is completely independent of the bandwidth. In other words, if you happen to like to use wider bandwidths (as I do) in order to more easily hear other signals on the band, the KDSP2 permits you to switch in noise reduction (NR) while maintaining your current bandwidth - whether it be wide or narrow. This also means of course that absolutely NO additional ringing is introduced when the NR is engaged, since it does not restrict bandwidth. You mentioned that you've "never found a DSP unit that has the ability to change an unreadable weak signal in noise, to a readable one", and I would say that I pretty much agree. However, while working with the KDSP2, I've noticed that I find myself invariably engaging the NR whenever I encounter an extremely weak signal, even if the band is not particularly noisy at the time, and it definitely helps. The greater the background noise, the more effective the NR seems to be. I still think that the human ear/brain does the best job of pulling signals out of noise, but as anyone knows who has strained to make out the callsign of a weak station sitting right at the noise level, it can be a very fatiguing experience. This is where the NR excels - by removing irritating static pops and ticks, and thereby providing the ear/brain with a much less distracting environment in which to work. In other words, it provides a major reduction in listening fatigue. Throughout the testing period, I had the interesting opportunity to perform side-by-side comparisons between the K2/KDSP2 and my ICOM 746PRO's DSP NR. I had a coaxial switch set up, which enabled me to switch the antenna instantaneously between rigs, and during the many hours spent testing, there was never a situation in which the 746PRO's NR exceeded the performance of the K2/KDSP2's. Of course, in my opinion the K2, even without the KDSP2, is the best sounding CW receiver I've heard (and, with the QTH being about 2 miles from the Ohio AES store, I've heard pretty much all of them), and now the KDSP2 extends that margin even more. I think it's important to recognize what DSP can and cannot do. It cannot, as far as I've been able to determine, pull a signal which is S6 out of an S7 noise level. I am aware of only two ways in which signals which are actually below the noise level can be extracted. One, is via the Noise Blanker - if the noise is of the right type. Fortunately for us K2 users, the KNB2 is an excellent noise blanker, and if the noise has the right spectral content, the KNB2 can virtually eliminate it, thereby enabling the reception of signals which were below the noise level. Another device which also can actually eliminate noise, is a noise nulling device such as the MFJ-1025/1026, which can completely null out interference - provided that the noise source is from a single direction. Neither of these systems however, is very effective against static crashes due to electrical storms. However, a well designed DSP noise reduction system, such as the KDSP2 is very effective at reducing static crashes, as well as any other type of continuous, white-noise-like interference, and greatly reduces listening fatigue, making for much more enjoyable operating. The KDSP2 also permits the user to fine-tune the noise-reduction system, by providing adjustments for 'Beta' and 'Decay' (loosely analogous to an AGC system's attack and decay parameters), as well as the NR Gain. The excellent Technical Note and Glossary which Lyle wrote, really helps to explain these parameters. Regarding the bandpass filters of the KDSP2, for each of the modes - CW, SSB, DATA, there are four filters, which are selected in the same manner as the AF1 and AF2 filters of the KAF2 are selected - except that for the KDSP2, we have four filter settings rather than two. Each of these filters have parameters which can be changed as desired, including filter center frequency and bandwidth (for CW), low-pass and high-pass corner frequencies for SSB, and filter gain for all modes. Additionally, each of the four possible CW filter positions have a 'Normal' and 'Soft' position which is easily set via the menus. The selection of these filters is completely independent of the I.F. filter settings. The point here is that although the KDSP2 comes with some carefully-determined default settings, they are all adjustable, for those of us who are inclined to experiment a bit. In summary, now that I've been using the KDSP2, I wouldn't want to be without it. I had a great time during testing, trying to find weak CW signals buried among QRN and QRM, and then using the KDSP2's NR and filters to pull them through. I hope this helps, Vic. 73, Dale - WA8SRA +++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "'Lyle Johnson'" , Subject: RE: [Elecraft] New KDSP2 Advanced DSP Filter for the K2 Date: Thu, 8 May 2003 08:58:31 +0200 Can we congratulate Lyle, KK7P, for getting his DSP development project accepted by Elecraft as a K2 option? 73, Sverre ------------------ Sverre Holm, LA3ZA www.qsl.net/la3za ++++++++++++++++++ Date: Thu, 08 May 2003 07:22:21 -0400 From: Dale Boresz To: elecraft at mailman.qth.net Subject: Re: [Elecraft] New KDSP2 Advanced DSP Filter for the K2 Charles Greene wrote: > What DSP functions does the DSP unit have? NR, Automatic notch, band > pass, and if band pass, what are the bandwidths? Are the specs posted > on the web site? I looked a few days ago and didn't find them. Check out: http://www.elecraft.com/KDSP2/kdsp2.htm -Dale ++++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] New KDSP2 Advanced DSP Filter for the K2 Date: Thu, 8 May 2003 06:22:52 -0700 > Can we congratulate Lyle, KK7P, for getting his DSP development project > accepted by Elecraft as a K2 option? He gratefully accepts those congratulations. Thank you! -Lyle ++++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] New KDSP2 Advanced DSP Filter for the K2 Date: Thu, 8 May 2003 06:28:19 -0700 Hello Neill! > >SSB mode includes an automatic notch filter > > I assume this automatically scans for a constant tone and notches it > out. Is it capable of finding two or more tones and simultaneously > notching them all? It can handle more than one tone. The notch is deeper on a single tone, which is the most common occurrence of this type of interference. -Lyle +++++++++++++++++++ Date: Thu, 08 May 2003 09:28:17 -0400 From: Dale Boresz To: elecraft at mailman.qth.net Subject: Re: [Elecraft] DSP - 4 questions & a LONG answer Wallace, Andy wrote: >>the KDSP2 comes with some carefully-determined >>default settings, they are all adjustable, for those of us who are >>inclined to experiment a bit. >> >> > >Can they be easily reset to factory default? (Either listed >in the manual pages for reference or by pressing a key on >the rig?) > >Andy > > > > Andy, Yes, the factory defaults are listed in the manual, and can easily be restored individually as desired. -Dale +++++++++++++++ Date: Thu, 08 May 2003 09:30:04 -0400 From: Dale Boresz To: elecraft at mailman.qth.net Subject: Re: [Elecraft] DSP value? Andrew Catanzaro wrote: > Headphones are absolutely necessary for good CW copy because putting > the source of the CW at the ear eliminates multipart distortion that > causes the brain to work overtime in copying even in-the-clear > signals. So when I hear something on the speaker I want to hear > better, I just put the cans on my head. I leave the filtering > wide-open on the TimeWave and use the KAF2 when needed. > I agree completely. However, when you put on the headphones, you are also able to hear the noise surrounding the signal that much clearer as well. This is where the noise-reduction of the KDSP2 really helps; it reduces that surrounding noise to a level that makes it much less distracting, without changing the level of the desired signal. The result is that your ear/brain doesn't have to work as hard to separate the signal from the noise, and copy is far more enjoyable. > It's a great filter that doesn't ring, and there's no digital bandwidth > that's narrower that's more useful! > I have been a long-time fan of the KAF2 (being primarily a cw op), and being one of the KDSP2 field testers, I have also had the opportunity to work with the KDSP2 on the air for some weeks now. While I've always liked the character of the audio with the KAF2 filter engaged, it accomplishes this at the expense of reduced bandwidth - whether the reduction is needed or not. Many times I have engaged the KAF2's filter only to help lift a weak signal out of the noise, even when there were no other signals around. Being one who prefers a wider bandwidth for general operation, I find the ability of the KDSP2 to reduce noise independently of bandwidth, to be one of it's most appreciated features. In short, the KAF2 is a wonderfully elegant and effective product, but the versatility and effectiveness of the KDSP2 is what keeps it firmly attached to my K2. :-) 73, Dale - WA8SRA ++++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] DSP: More Questions and Request for WAVE files Date: Thu, 8 May 2003 07:31:19 -0700 Hello Jim! > 1. Why doesn't the auto-notch work in CW mode? If it did, then it would have to delay for a second or so before it became effective so it wouldn't notch out the CW signal you were trying to hear. I chose to make it work immediately. On CW, you can tighten the bandwidth to get rid of heterodynes. On SSB, you generally can't, so having the notch work immediately seemed a reasonable choice. > 2. Why is the Noise eliminator off by default in CW mode? Does > this imply that it works better in SSB than in CW mode? It is off by default in SSB, too. You just tap a button to toggle it on and off, in either mode. It works fine in CW. > 3. KAF2 has a very pleasing sound in that hiss etc is removed. Is > this in part a function of the "soft slopes" of the audio filter? > Does the KDSP2 have a similar pleasing sound? Some operators think the KDSP2 "soft" filter settings at around 200 - 300 Hz bandwidth have a similar sound to the KAF2. 73, Lyle KK7P ++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] DSP: More Questions and Request for WAVE files Date: Thu, 8 May 2003 07:38:41 -0700 > > 2. Why is the Noise eliminator off by default in CW mode? To further clarify, it is off when you first turn the unit on after you have built in in both CW and SSB modes. If it defaulted on, you might think there was a problem in your audio when you first turned on the K2 after installing the KDSP2, because the background noise would be so much weaker than before... When you turn on your K2, if the denoiser was on the last time you used the KDSP2, it will be on when you next use the KDSP2. The state of the denoiser and notch and are retained through power cycles of the K2. 73, Lyle KK7P +++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] DSP - 4 questions Date: Thu, 8 May 2003 17:32:31 -0700 Hello Bill! > Now, with the KDSP2, there's no such analog filter. Correct. It is a digital filter, not an analog filter. > Looking at the > schematics, it appears the audio goes directly through the A/D D/A chip. > I don't see any way that it is bypassed, unless that happens internally. When the DSP is commanded to the bypass mode, the CODEC chip bypasses the A/D and D/A and operates as an amplifier. > Other than a single pole R/C filter, there doesn't appear to be any other > low-pass operations to eliminate the hiss, even if the A/D D/A can be > bypassed. Correct. If the filter is on, the hiss is gone. If the filter is bypassed, it is, well, bypassed :-) > So, this implies that the low-pass operation takes place in the DSP > itself. The bad point about that is that the digitizing operation > introduces quantization noise, which limits the dynamic range of the > audio. Unless peak signals are hitting the maximum limits of the A/D > converter, this dynamic range is going to be substantially less than the > 90 dB specified. The dynamic range capability is 90 dB. The dynamic range of audio presented to the DSP if AGC is ON is much less than this. For example, if you have Spectrogram, tune in a loud signal and look at the noise floor. On my K2 it is much less than 90 dB below the peak of the strongest signal. Most strong signals I have examined have a signal-to-noise ratio of 25 to 45 dB. The 4 MHz "test tone" heard on 80 meters on a K2, for example, is about 40 dB above the noise on my K2. Giving away 20 dB at the top leaves 70 dB capability, and in this case we still have 30 dB of margin. Looked at another way, if you are listening to an SSB signal, the transmitted IMD products are usually only 30-35 dB or so below PEP, limiting the useful dynamic range of the signal to about the same 30-35 dB. I believe the A/D and D/A capability of the KDSP2 far exceed the needs of good communications quality signals. > While I like the features of the DSP, I'm worried that having the A/D > conversion in line all the time will slightly raise the noise floor of > the rig, especially for weak signals. And I don't like the idea of > disabling the filter, since that will re-introduce the audio hiss. The only reason to disable the DSP filter is to save power if you are running on batteries. Your ears may be much better than mine. I don't hear any increase in noise floor, nor do I measure one. If I use the sig gen, the weakest signal I can discern is no different with DSP or without. The quality of the signal and its apparent signal-to-noise ratio does change though, in most cases in definite favor of having the DSP. I do hear a marked decrease in noise, though, with virtually any filter selected. The narrower the filter, the less noise bandwidth and the less noise. And the denoiser drops the background noise I hear by 10-20 dB depending on how it is set up. But this sort of thing is highly subjective. YMMV 73, Lyle KK7P ++++++++++++++++++ Subject: RE: [Elecraft] DSP - 4 questions Date: Thu, 8 May 2003 22:32:15 -0400 From: Bill Coleman To: "Lyle Johnson" , On 5/8/03 8:32 PM, Lyle Johnson at wa7gxd at fidalgo.net wrote: >Your ears may be much better than mine. I don't hear any increase in noise >floor, nor do I measure one. If I use the sig gen, the weakest signal I can >discern is no different with DSP or without. The quality of the signal and >its apparent signal-to-noise ratio does change though, in most cases in >definite favor of having the DSP. This is good news. It is something to be sufficiently concerned enough to try and measure. I believe the original W9GR DSP used only an 8-bit CODEC, which caused a significant addition of quantization noise. Telephone CODECs are compandored (A-law or mu-law) to an equivalent of 14-bits. Perhaps 16 bits is sufficient for radio, so long as it follows the major selective element and the AGC. For rigs with IF DSPs providing all the selectivity, dynamic range is the achillies heel -- hence the 20 to 24-bit CODECs. Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 ++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] DSP - 4 questions Date: Thu, 8 May 2003 22:02:36 -0700 Hello Bill! > It is something to be sufficiently concerned enough to try and measure. I > believe the original W9GR DSP used only an 8-bit CODEC, which caused a > significant addition of quantization noise. Yes, it was an 8-bit part. > Telephone CODECs are compandored (A-law or mu-law) to an equivalent of > 14-bits. I think it is 12 bits, but who's counting :-) > Perhaps 16 bits is sufficient for radio, so long as it follows > the major selective element and the AGC. Yes. The AGC is fairly important here, and that the AGC "sees" the bandwidth (or more) that the DSP sees. > For rigs with IF DSPs providing > all the selectivity, dynamic range is the achillies heel -- hence the 20 > to 24-bit CODECs. Exactly. 73, Lyle KK7P ++++++++++++++++++ From: "Leonard, David" To: "'elecraft at mailman.qth.net'" Subject: Re: [Elecraft] DSP value? Date: Fri, 9 May 2003 12:50:17 -0400 Dale: Thank you for the very prompt and lucid response. Since my first post I spent some time at lunch today to download the design notes from the website and looked at the pictures carefully. (NOTE: I highly recommend, to anyone contemplating the DSP module, that they download the design notes) I was so impressed I ordered my DSP unit immediately. Another thing I noticed NO #%#$ at %^&%% Toroid winding! Now I have a decision to make. Plan A: I buy another K2 to use strictly for portable CW use with the low drain KAF2? or........ Plan B: I sell the KAF2..... Hmmmmmm Decisions Decisions... 8-) I'm tending towards Plan A but I may get flack from the finance director (the XYL 8-) 73 de Dave K9FZJ ++++++++++++++++