Hi, I have modified the usrp_wfm_rc.py script to capture samples of an FM signal and write them to disk, and a second script to demodulate and playback the samples.
The scripts are available here: http://rrsg.ee.uct.ac.za/members/aadil/ I have 3 questions: 1) 1 000 000 samples writes a file 8 000 000 bytes (7.6Mb) This suggests each sample is 8bytes; 4bytes I and 4bytes Q. Is my assumption correct? Considering that the ADC produces 12bit samples, I would expect that each I and Q sample pair would be 4bytes. 2bytes I and 2bytes Q. Please can someone advise where i've missed some understanding. 2) With reference to the above question, where can I find further details regarding the function of the gr.sizeof_item identifiers, in particular gr.sizeof_gr_complex. 3)If my file is 1 000 000 samples and my audio rate is 32KHz( I understand this to be 32K samples/second) I expect my playback time to be (1e6/32e3) = approx 30s, however when I play the file I get only approx 3s playback time. Im not sure where i've gone wrong. Thanks for your time, and I look forward to and appreciate your advice. Aadil _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
