Hi, I am running an experiment where I would like to monitor the magnitudes of a bursty, constant-envelope signal using the USRP and a DBSRX receiver. I am seeing some quasi-periodic amplitude transitions and wanted to know if this could be related to an AGC. Why I believe it is AGC-related is because the amplitude transitions occur ONLY on leading-edge boundaries (and never intra-burst). What I see magnitude-wise in Matlab based on data from usrp_rx_cfile.py is something like:
_---_---_---_|||_|||_|||_|||_|||_---_---_---_|||_|||_|||_|||_---_---_|||_|||_|||_--- ... (magnitude vs. time --- please excuse my ascii art:) where there are really only two magnitude levels ( ||| and --- , and interburst 'silence' is denoted as _ ). Furthermore, I ran another experiment using the same bursty, constant envelope signal using 2 DBSRX receivers in a single USRP (with the proper mux of 0x3210). Both receivers experienced the same phenomenon, however there was some more 'interesting' behavior. When the DBSRX on side A transitioned from high to low, the DBSRX on side B transitioned from low to high. This was the case for multiple runs, and again the transitions only occured at leading edge times. In summary my questions are as follows: 1) Is there an AGC in the DBSRX? 2) If yes, can I turn it off? Thanks in advance for any ideas, recommendations, or comments! Rob -- View this message in context: http://www.nabble.com/DBSRX-AGC--tp24021532p24021532.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
