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 <kl...@acsalaska.net> 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 <c...@mac.com> > Subject: Re: [Elecraft] K3 and USB Audio Codec > To: Elecraft Reflector <elecraft@mailman.qth.net> > Message-ID: <2e745a19-d7ed-4bb1-a9c6-d7080d6e1...@mac.com> > 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 dubus...@hotmail.com > ====================================== > *temp > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
