XCore Exchange

Status: Under development
License: Custom Licence

This project builds on previous efforts to develop a low-cost software defined radio (SDR) module. The module used here is documented at the sdrtrack web site and was originally designed to interface with one of Digilent's FPGA development boards. Being a long-time fan of the Inmos Transputer (I still have a T800-based PCI card in my junk box), adapting the system for the XMOS device seemed natural. The module is based on TI's AFEDRI8201 PGA/ADC/DDC and also includes a LNA, LPF and RF bypass switch. The board is controlled via SPI and data is supplied as framed serial I&Q (32 bit frames, 16 bit I and 16 bit Q). At present, the implementation has been tested with 80 MHz digitizer, 20 Mbps serial data, and decimation of 160 (500 ksps I&Q). The XC application includes 4 threads; (1) serial data interface, (2) FM demodulator, (3) FIR low-pass filter, and (4) one-bit DAC. The one-bit output passes through an external LPF and to the mic input of the development platform. The antenna is connected directly to the AFEDRI8201 (bypass selected) and FM broadcast stations are bandpass sampled (tune to f-80 MHz). I've been listening to local broadcast stations using the current implementaion. Improvements in the demod, filter, and DAC could be made to further improve the audio. Figure shows the SDR module, XK-1, XTAG, and low-pass filter.
Plans

Move the module interface to the XTAG2 and port code

Eliminate the demod, filter, and DAC and replace with the XMOS USB Audio code (send I&Q as stereo audio)
Images:

I am also a fan of the Transputer and have a board somewhere in my junk box. I have been thinking that the XMOS parts have the speed to DSP from DC to 1+ GHz with the inclusion of front end tuners. Your project may inspire a more powerful class of spectrum analyzers for the internet RF designers.

Good Luck !

Xmos's tight latencies, add in concurent event channeling, makes SDR on XMOS compelling.
Xcore's community is such a symbios of talent the sky's the limit. Good luck with this one.
Radio's are very enpowering especially the one's with good fourier transforms.

Looking foward for more of this...

Whizz Systems is one of the leading companies on advanced FPGA design and FPGA development capabilities. Being a vendor neutral Advanced FPGA Design Center the work done at Whizz ranges from simple glue logic to the highly complex System on a Chip (SOC) designs that include soft core processors.