It's been suggested that I modify my ARISSat-1 BPSK-1000 telemetry demodulator/decoder to accept wideband quadrature (I & Q) recordings like those produced by most of the software defined radios out there.
This is fundamentally not that hard, but first I need some information. How many people could actually use this? What is the format of the recorded files? Is there a standard, or does each make of SDR produce its own? If I could get a good sample wideband quadrature recording of the ARISSat-1 downlink that includes the BPSK beacon, I could use it for testing. Ideally there would be no need for any manual tuning because the wideband recording would always contain the beacon regardless of Doppler. All tuning would be in the demodulator software. This might be a little compute-intensive so I can't guarantee that it'll run in real time on older computers. I already make pretty heavy use of the Intel SSE (vector arithmetic) instructions for FIR filtering and Viterbi decoding. The SSE2 set introduced with the Pentium 4 has been especially useful, so I would consider the P4 (or the AMD equivalent) a minimum requirement. Of course, the newer and faster the CPU, the better. I also make use of multiple CPU cores, particularly during the acquisition phase, so the newer CPUs with lots of CPU cores would also be preferred. 73, Phil _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
