I am using the following code: https://www.cgran.org/browser/projects/cmu_macs https://www.cgran.org/browser/projects/cmu_macs and this is a request for help with anyone with experience with that code. I have spent a fair bit of time looking through gmsk.cc, cmac.cc, .... but I cannot find the parts that control the gain of the VGA on USRP1. There are some gain settings but they seem to be for filters. The CMAC code makes use of (now deprecated) mblock messaging, but I am assuming that it is still built on top of the normal gnuradio base (I believe with a patch to permit mblocks).
How do I determine which gain control blocks (e.g. AGC/AGC2/..) that it is using, if any? George Nychis worked on the project but is less familiar with the physical layer code, since his project is at a higher MAC layer. Does anyone else out there know this off the top of their head? When I look at data being received from transmitters placed at long and then short distances from the USRP using https://www.cgran.org/browser/projects/cmu_macs/trunk/src/apps/rx_file.cc https://www.cgran.org/browser/projects/cmu_macs/trunk/src/apps/rx_file.cc , the amplitude of the IQ data, as seen in gmsk.cc, is relatively constant. This must be a sign of adaptive gain control (somewhere?) or of saturating elements in the RF to baseband path, right? Alternatively, could anyone suggest a method to query and/or control the gain settings of the USRP1 from C++ source code? As an alternative to using the cmu-macs code, I'd also be interested in any working gnuradio companion implementations of a QPSK/MSK demodulator too. This would enable me to use explicit gain control elements (like the AGC blocks) although I am quite familiar with the c++ source code in the cmu_macs project now and don't really want to abandon it given the time I've invested already. Thanks, in advance, / David Knox -- View this message in context: http://old.nabble.com/Where-is-the-gain-control-in-cmu_macs--tp30762024p30762024.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
