+++++++++++++++++++ See KSDP2 Info - Info before shipment... +++++++++++++++++++ Date: Tue, 20 May 2003 18:02:53 -0700 From: Wayne Burdick Organization: Elecraft To: Elecraft Subject: [Elecraft] anyone build their KDSP2 yet? We sold about 60 first-production-run KDSP2 kits at Dayton. Just wondering if any of them are up and running. Any feedback on the manual, user interface, and performance would be appreciated. 73, Wayne N6KR ++++++++++++++++++ Reply-To: "Dave Larson" From: "Dave Larson" To: "Wayne Burdick" , "Elecraft" Subject: Re: [Elecraft] anyone build their KDSP2 yet? Date: Tue, 20 May 2003 21:38:12 -0400 I started mine tonight. Probably will finish it Thursday or Friday nite. All the parts were there, no problem so far. Dave K8AA ++++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] KDSP is done Date: Thu, 22 May 2003 07:17:15 -0700 Hello Kevin! > Can you please clarify your statements about the KDSP > and it causing distortion in the audio.... > I have used a JPS Communications NIR-10 DSP unit for > several years. It was an expensive purchase at one of > my trips to Dayton... I would expect the KDSP2 would > behave in a similar fashion. Please read the paper I wrote and which is on the Elecraft website (http://www.elecraft.com/KDSP2/kdsp2design.pdf) about the design of the KDSP2. It explains the design decisions for the algorithms used. The JPS unit you mention uses spectral subtraction for its noise reduction; the KDSP2 uses least-mean-squares. Each has its strengths and weaknesses; both add audio artifacts. The artifacts sound different between the two methods. The KDSP2 allows you to vary all three parameters which affect the noise reduction: filter length, coefficient attack, and coefficient decay. This unparalleled flexibility allows you to tailor the amount and type of noise reduction to suit your personal audio tastes and preferences under various band conditions. 73, Lyle KK7P ++++++++++++++++ From: "Lyle Johnson" To: , Subject: RE: [Elecraft] dsp problem? Date: Thu, 22 May 2003 10:10:02 -0700 This is not normal. The description of the sound is as if you have the AGC turned off and are receiving a really loud signal. Try backing down the RF gain cotnrol. If that clears it up, you may have an AGC problem. -Lyle > -----Original Message----- > From: elecraft-admin at mailman.qth.net > [mailto:elecraft-admin at mailman.qth.net]On Behalf Of > gwlillie at adelphia.net > Sent: Thursday, May 22, 2003 9:42 AM > To: elecraft at mailman.qth.net > Subject: [Elecraft] dsp problem? > > > Maybe I have a problem with my dsp unit. Even at the 1 level of > noise reduction the audio sounds tinny and it will make the built > in speaker shriek. Turning the audio to min helps but it seems to > overload with more volume added to hear the weak ones. This is on > ssb. I'm sorry but with my unit I have a harder time > understanding the audio. On cw it is much better and distortion > does not make too much difference. It seems to me the lowest > level of noise reduction is too much. And I intend to play with > the settings and the gain. It may be my agc because I have it set > at a more aggressive level (3.5v). I will have to ask Eric about > this. Everything seems to function properly. I like the ssb > filters, without noise reduction they are better than the crystal > filter. With dsp filters in the noise is cut way down to start. I > will only use noise reduction when I have to. > ++++++++++++++++++ Date: Thu, 22 May 2003 10:53:16 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: Elecraft List Cc: QRP-L , GQRP Subject: [Elecraft] New .wav files of KDSP2 noise reduction on SSB and CW As requested, we have added demo files of the KDSP2 in action using noise reduction for CW and SSB signals to our KDSP2 web page. The links are near the bottom of the page. See: http://www.elecraft.com/KDSP2/kdsp2.htm These recordings were made with the DSP set for a fairly aggressive noise reduction. The KDSP2 can also be adjusted from the K2's front panel for more or less noise reduction as you like. it can also be set to run with the auto notch and narrow bandwidth filter settings at the same time as noise reduction. 73, Eric WA6HHQ http://www.elecraft.com +++++++++++++++++ Date: Sat, 24 May 2003 11:29 +0100 (BST) From: davejewell at cix.compulink.co.uk (Dave Jewell) Subject: RE: [Elecraft] KDSP2: (Another)Request for WAVE file To: elecraft at mailman.qth.net Reply-To: davejewell at cix.compulink.co.uk In-Reply-To: <20030524080257.643F6328A63 at mailman.qth.net> The problem with MP3 encoding is that it will often perform extraordinarily badly when listening to CW. You only have to listen to the readily downloadable practice morse sessions from W1AW to see what I mean. They will either sound fine or awful depending on the codec that you have installed into Windows Media Player. You can read more about this at: http://www.eham.net/forums/CW/663 Paradoxically, the more recent codecs are a lot worse than slightly older ones. The problem is that some codecs simply cannot handle continuous tones of one frequency - the MP3 encoding just falls apart. I would suggest that in order to hear what the DSP unit sounds like, you need something that's as close to the original as possible. MP3 + CW is a combination that will introduce far too many artifacts into the resulting output. The simplest solution is just to use WAV files and ZIP them up -- WAV files compress very well. Surely most people have got a ZIP utility these days? 73, Dave GW0LUA --------------------------------------- "Dan Barker" wrote: mp3 will be tiny. Convert it. Dan / WG4S / K2 #2456 ++++++++++++++++ From: "Lyle Johnson" To: "Elecraft Reflector" Subject: RE: [Elecraft] K2 DSP - Standardised Input for Comparison Testing Date: Sat, 24 May 2003 10:47:06 -0700 Hello Mike! > I've just read the article describing the design philosophy behind the new > K2DSP. The ability to adapt many of the filtering parameters is sure to > result in a large amount of dialogue on the reflector about what settings > are best for SSB, CW, RTTY etc. As you hint in your posting, band conditions vary widely. Noise conditions vary widely. Signal con... you get the idea. The ability to adjust the settings *while you operate* is important for those who like to tweak things. I can adjust the settings to make certain cases sound really great -- but in the real word of dynamically changing conditions, the resulting performance might be very poor. We picked default settings that seemed to give good results under typical conditions. But some people have very critical ears and are sensitive to certain kids of distortions, while others don't and aren't. Sort of like allergies, I suppose! In general, if you set the decay to very low values, you'll get better noise or carrier rejection - but at the expense of more pronounced artifacts. Similar with very high settings for beta. > However, individual assessment of settings > will be subjective unless there is a standardised input signal. Exactly! This whole topic is subjective. Personally, I think it should be. > What sort of empirical testing did the design team do? What if > anything did they use/do to standardise the input conditions? During Field Test, folks were asked to play..er..test and report back what they liked. We then averaged things, added a weighting factor (my vote counts for 3, yours for 1/2 :-) then got out the dartboard and the chimpanzees. But we selected the darts very carefully... 73, Lyle KK7P (ex VK6GXD) ++++++++++++++++ From: "Lyle Johnson" To: "Elecraft" Subject: RE: [Elecraft] KDSP2 Date: Sat, 24 May 2003 14:41:23 -0700 Hello Rich! > Only complaint so far is that it is inconvenient to get to the > clock, takes > more keystrokes to use VS KAF2 were you hit the display button once. Yes. It takes two keystrokes - hit DISPLAY, then press BAND+ and BAND- simultaneously. If the clock was the last display from the DSP, and you don't change modes or bands, then it will come up when you hit DISPLAY. 73, Lyle KK7P ++++++++++++++++ From: "Lyle Johnson" To: Date: Sat, 24 May 2003 20:08:52 -0700 Subject: [Elecraft] Learning DSP and the KDSP2 For those of you who are experimentally inclined, the ARRL book "Experimental Methods in RF Design" (EMRFD) has wonderful, practical tutorial DSP information in Chapters 10 and 11. The book is al ittle pricey, but worth every penny. And hey! Father's Day is coming (the female operators on this reflector already got their copy on Mother's Day). The example code on the book's CD-ROM can be adapted to run on the DSPx module. A variation of the DSPx is the pre-assembled DSP engine used in Elecraft's KDSP2. If you want to develop code for the KDSP2, learn about DSP in general, or embed a DSP module in your latest project, please visit www.kk7p.com for information on these modules and how to use them. You will also find the modified source and object code for EMRFD through that site. I used the DSPx and KDSP10 to develop and test the DSP code for the KDSP2, so I know they are tools that work. The source code for the DSP portion of the KDSP2 will be available by the end of June under the GNU open source license (GPL). What are you waiting for? Now, back to your regularly scheduled reflector traffic... 73, Lyle KK7P ++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] Clock in KDSP2 Date: Sun, 25 May 2003 07:36:56 -0700 Hello Roy! > I have looked through the manual and cannot find where additional > capacitance can be added to the RTC to slow it down. Like the KAF2, the KDSP2 clock is not a precision timepiece. However, with the open source DSP, perhaps someone (not me!) will write an application that decodes the calibration signals from a time standard broadcast and automatically updates the clock! Or monitors something on the internet and does the same thing... In the meantime, if you want to slow the clock down, increase the capacitance at C6 by replacing the capacitor or paralleling it with another. 73, Lyle KK7P +++++++++++++++ From: "Lyle Johnson" To: "Elecraft" Subject: RE: [Elecraft] K2DSP Date: Sun, 25 May 2003 07:45:15 -0700 Hello Mike! > My question is this: Since the K2DSP is (by necessity) menu > driven I've wondered how quickly one can adjust the settings > having to access various menus. The most commonly adjusted functions are available by 1 or 2 button presses: ONE BUTTON Press AFIL to sequence through the four filter settings you have set up for the current mode. In CW, for example, this is usually a series of filters at the same center frequency, but varying width. TWO BUTTON 1) Tap DISPLAY to bring up the KDSP2 menu 2) The KDSP2 main menu for CW will let you then toggle noise reduction on and off (tap BAND+), toggle between hard and soft filter shapes (tap BAND-) or adjust the amount of noise reduction (PRESS STORE). The KDSP2 main menu for SSB will let you toggle noise reduction on and off (tap BAND+), toggle the autonotch on and off (tap BAND-) or adjust the amount of noise reduction (PRESS STORE). The main menu for RTTY lets you adjust filter center frequency and width since notch and noise reduction are not available in this mode. *** More esoteric settings, like denoiser beta and decay, are buried a few menus deeper. 73, Lyle KK7P +++++++++++++ From: "Lyle Johnson" To: "Phil Wheeler" Cc: "Elecraft Reflector" Subject: RE: [Elecraft] K2 DSP - Standardised Input for Comparison Testing Date: Mon, 26 May 2003 09:21:42 -0700 Hello Phil! > Having used Spectrogram to adjust my xtal filters just > prior to building the KDSP2, I wonder if anyone has > used that software and a noise generator to compare > the K2 with DSP to without DSP. Would doing that > make any sense? This was done by some of the Field Testers during development. And of course, it is important to really watch the input levels or you'll display all sorts of artifacts that aren't really there. But you already knew that. > I'd try it but, unlike some others here (e.g., N0SS, > I've not doped out how to capture the Spectrogram > images to document the results. My version of Spectrogram is the older freeware one, so it doesn't make wonderful plots. But, you can do a screen capture under Windows, and then paste that into a diocument. 73, Lyle KK7P +++++++++++++++