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ha7ilm / csdr

A simple DSP library and command-line tool for Software Defined Radio.
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Help creating a working chain... #18

Closed michelinok closed 7 years ago

michelinok commented 8 years ago

Hi! I'm fighting with my receiver and csd for months...and cannot find a valid "chain" of commands to decode some audio... My receiver outputs samples at a samplerate of 192khz 24 bit integer... What i would like to do is: tune the receiver to a central frequency (for example 7070000) and decode an lsb audio signal at 7073000 (so +3 khz from the tuned freq) with a bandwidth of 2.7khz (standard ham audio bandwidth). The output of the soundcard is 44.100 (i'm using a raspberry 3 with the classic 3.5mm jack). The receiver outputs samples in this way: elad_sdr_24 7070000 0 | csdr... (where frequency is 7070000 and 0 means infinite samples).

Can someone provide me the command to use?

Many thanks!

'73 de IU5HES

http://www.iu5hes.it

ha7ilm commented 8 years ago

I can't try it, anyway I guess that:

elad_sdr_24 7070000 0 | csdr convert_s24_f | csdr shift_addition_cc $(python -c "print (7073000-7070000.)/192000") |  csdr fir_decimate_cc 4 0.05 HAMMING | csdr bandpass_fir_fft_cc -0.1 0 0.05 | csdr realpart_cf | csdr agc_ff | csdr limit_ff | csdr convert_f_s16 | mplayer -cache 1024 -quiet -rawaudio samplesize=2:channels=1:rate=48000 -demuxer rawaudio -
ha7ilm commented 8 years ago

There might as well be an endianness problem, which can be fixed with csdr convert_s24_f --bigendian.

michelinok commented 8 years ago

I'll try asap and let you know. Please, can you explain where is the audio bandwidth calculated? (I mean the 2.3 or 2.7 khz... cannot remember the ham standard)

Http://www.iu5hes.it

Il 09 ott 2016 20:42, "András Retzler" notifications@github.com ha scritto:

I can't try it, anyway I guess that:

elad_sdr_24 7070000 0 | csdr convert_s24_f | csdr shift_addition_cc $(python -c "print (7073000-7070000.)/192000") | csdr fir_decimate_cc 4 0.05 HAMMING | csdr bandpass_fir_fft_cc -0.1 0 0.05 | csdr realpart_cf | csdr agc_ff | csdr limit_ff | csdr convert_f_s16 | mplayer -cache 1024 -quiet -rawaudio samplesize=2:channels=1:rate=48000 -demuxer rawaudio -

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ha7ilm commented 8 years ago 
csdr bandpass_fir_fft_cc -0.1 0 0.05

...will have around 4.8 kHz.

csdr bandpass_fir_fft_cc -0.05625 0 0.002

...will have 2.7 kHz, with a transition BW of 96 Hz.

ha7ilm commented 7 years ago

I hope it is solved by now.