K3 and USB Audio Codec
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I have kind of ignoring this thread, but just realized that it
addresses a long-term desire of mine. I would like to tap the IQ data for both the main and sub receivers simultaneously for pc processing with special eme sw. I can do one channel using the SDR-IQ but there are advantages to having two channels (polarity diversity reception). Both channels need to be phase-locked in freq. My discussions with Wayne indicate that it may be possible interface at a later time thru the P3. To take advantage of the 15-KHz SDR in the K3 this interface will eventually very desirable. That opens the K3 to equal footing with other SDR's to fulfill the no obsolescence promise of SDR. 73, Ed - KL7UW ------------------------------ Message: 6 Date: Tue, 13 Jul 2010 10:10:17 -0700 From: Kok Chen <[hidden email]> Subject: Re: [Elecraft] K3 and USB Audio Codec To: Elecraft Reflector <[hidden email]> Message-ID: <[hidden email]> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes On Jul 10, 2010, at 7/10 2:57 PM, Joe Subich, W4TV wrote: > If one were going to provide digital output, it would be far better > to stream the raw in I/Q data from the DSP's ADC via firewire rather > than push it through two additional A/D and D/A steps and reduce it > to a single channel of audio. FireWire is not necessarily a great solution either. It will definitely require special drivers at the computer end (viz, the Edirol FA-66 that is common in ham SDR circles). One good connection that I have come across is S/PDIF that is available on the Icom IC-7800. It allows a connection between the radio and the computer that is completely non-galvanic. No ground loops, no RFI, down to -144 dB. S/PDIF provides an audio path with up to 20 bits of resolution (about 120 dB, with 1 bit being 6.02 dB), with 24 bits being an option by using the extra 4 steering bits as data. The standard sampling rate for S/PDIF is 48,000 samples per second stereo, which would support almost 50 kHz of bandwidth on an baseband I/Q channel. S/PDIF provides up to about 30 feet separation between equipment. Both Firewire and S/PDIF lacks a standard way of passing control/ status signals. The Flex-5000 (which uses FireWire) used to hack into the MIDI (Musical Instrument Digital Interface) channel for control/ status; but I have not been following that development and it might have since changed. The Icom IC-7800 goes through its regular CAT path (RS-232 or CI-V, you get to choose, I believe). In any case, if you want a rig like the K3 to support 123 dB of dynamic range I/Q output, it will not come cheap. The Asahi AK-5394A is probably the most expensive component in the front end of the Flex-5000, and you have to be very careful with the circuit layout to get a -125 dB noise floor when mixing analog and digital components. We are definitely not talking about 16-bit codecs like the one in the SignaLink USB -- which by the way, is a TI/Burr-Brown PCM-2902, and it is not the $20 that people have been mentioning, but is $5.85 at DigiKey :-). 73 Chen, W7AY 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-QRT*, 432-100w, 1296-QRT*, 3400-fall 2010 DUBUS Magazine USA Rep [hidden email] ====================================== *temp ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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You're still not going to get access to both IFs at the same time though...
~Brett (N7MG) On Wed, Jul 14, 2010 at 4:40 PM, Edward R Cole <[hidden email]> wrote: > I have kind of ignoring this thread, but just realized that it > addresses a long-term desire of mine. I would like to tap the IQ > data for both the main and sub receivers simultaneously for pc > processing with special eme sw. I can do one channel using the > SDR-IQ but there are advantages to having two channels (polarity > diversity reception). Both channels need to be phase-locked in > freq. My discussions with Wayne indicate that it may be possible > interface at a later time thru the P3. > > To take advantage of the 15-KHz SDR in the K3 this interface will > eventually very desirable. That opens the K3 to equal footing with > other SDR's to fulfill the no obsolescence promise of SDR. > > 73, Ed - KL7UW > > ------------------------------ > > Message: 6 > Date: Tue, 13 Jul 2010 10:10:17 -0700 > From: Kok Chen <[hidden email]> > Subject: Re: [Elecraft] K3 and USB Audio Codec > To: Elecraft Reflector <[hidden email]> > Message-ID: <[hidden email]> > Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes > > > On Jul 10, 2010, at 7/10 2:57 PM, Joe Subich, W4TV wrote: > > > If one were going to provide digital output, it would be far better > > to stream the raw in I/Q data from the DSP's ADC via firewire rather > > than push it through two additional A/D and D/A steps and reduce it > > to a single channel of audio. > > FireWire is not necessarily a great solution either. It will > definitely require special drivers at the computer end (viz, the > Edirol FA-66 that is common in ham SDR circles). > > One good connection that I have come across is S/PDIF that is > available on the Icom IC-7800. It allows a connection between the > radio and the computer that is completely non-galvanic. No ground > loops, no RFI, down to -144 dB. > > S/PDIF provides an audio path with up to 20 bits of resolution (about > 120 dB, with 1 bit being 6.02 dB), with 24 bits being an option by > using the extra 4 steering bits as data. > > The standard sampling rate for S/PDIF is 48,000 samples per second > stereo, which would support almost 50 kHz of bandwidth on an baseband > I/Q channel. S/PDIF provides up to about 30 feet separation between > equipment. > > Both Firewire and S/PDIF lacks a standard way of passing control/ > status signals. The Flex-5000 (which uses FireWire) used to hack into > the MIDI (Musical Instrument Digital Interface) channel for control/ > status; but I have not been following that development and it might > have since changed. The Icom IC-7800 goes through its regular CAT > path (RS-232 or CI-V, you get to choose, I believe). > > In any case, if you want a rig like the K3 to support 123 dB of > dynamic range I/Q output, it will not come cheap. The Asahi AK-5394A > is probably the most expensive component in the front end of the > Flex-5000, and you have to be very careful with the circuit layout to > get a -125 dB noise floor when mixing analog and digital components. > > We are definitely not talking about 16-bit codecs like the one in the > SignaLink USB -- which by the way, is a TI/Burr-Brown PCM-2902, and it > is not the $20 that people have been mentioning, but is $5.85 at > DigiKey :-). > > 73 > Chen, W7AY > > > > 73, Ed - KL7UW, WD2XSH/45 > ====================================== > BP40IQ 500 KHz - 10-GHz www.kl7uw.com > EME: 144-QRT*, 432-100w, 1296-QRT*, 3400-fall 2010 > DUBUS Magazine USA Rep [hidden email] > ====================================== > *temp > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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