Have you taken a gander at http://www.arrl.org/tis/info/vhfproj.html The DSP-10: An All-Mode 2-Meter Transceiver Using a DSP IF and PC-Controlled Front Panel
It uses a dedicated DSP IC but you should be able to easily modify it or at least get some ideas ... not sure it could be done for under 100 bucks Other ideas would be to download to a fixed IF and there you can easily get your quadrature using a fixed (or limited range) BFO using inductors/capacitors like the KK7B designs ... this is a route I have contemplated before the I-Q VFO project came along, I was going to use a 9850 DSS with a PLL and downconvert and get my I-Q signals from the IF .... John --- In [email protected], "Rud Merriam" <[EMAIL PROTECTED]> wrote: > May as well be ambitious at the start. I can scale back as I run into > issues. > > My revised list based on your comments: > > 1. FM transceiver for experimenting with data protocols. > 2. Cost < $100 built. (Probably a big stretch goal.) > 3. Audio is handled with a PC sound card interface for DSP processing on > both TX and RX. > 4. Work on 50 - 440 Mhz with minimal component changes, preferable only the > RF filters. > 5. Software control of frequency. > 6. Adaptable to a full digital protocol RF modem with the addition of DSP > processing. > > The only real change is the transceiver is FM only since that is the typical > mode on these bands for data. > > The APRS transmitter is a simple FM transmitter. If there is an alternative > I would be interested in seeing it. Maybe it is overly simple. > > Yes, I was going to strip out most of the audio in the miniR2 design. Isn't > that how design is done? Grab a piece of this circuit, some of that one, and > parts of still another 3 or 4. <g> > > One reason the BIQR looked interesting is because it doesn't have the > additional audio and looked simpler overall for the RF / IQ portion. I am > concerned about it not keeping the IQ in syncrhonization. > > This may not be as much an SDR as usually discussed here. But since it is IQ > oriented this seems to be a good place for the discussion. > > What do yo mean by "A good thing about DSP vs the hardware phasing approach > to single-signal detection is that the DSP can be programmed to correct > minor RF phasing errors." Do you mean using a high-speed ADC to sample the > RF and then decimating to get the IQ? > > I am looking for ideas so your message are great. Thanks. > > Rud Merriam > K5RUD Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
