John --
Have you looked at all at the Siren board? It's part of the HPSDR and Suitsat II projects: a low-power, low-cost SDR engine using the dsPIC33F embedded controller from Microchip. The current design uses 10 MHz RF in and out, and the QSD and QSE for complex sampling and excitation. There is also an onboard TI stereo codec for I/O in the audio range. Digital data can be synchronously imported and exported over one or more SPI buses.
It's not perfectly general. Many of the algorithms we'd like to run on it need to be tailored to the hardware in a way that's more constrained than we'd like in general. That notwithstanding, it should be capable of handling 48 kHz bandwidth, and muxing and demuxing several channels within that span.
So far, as far as I know, only prototypes and first-gen boards are in circulation. The power consumption is already very low; there's a lot of board real estate eligible for shrinking as well.
Frank
On Dec 21, 2007 11:02 PM, John Gilmore gnu@toad.com wrote:
The thing does appear to have sufficient horsepower to do some DSP. ...