Hi, I'm still in the exploring phase of my GNU radio work and currently ran into an annoying problem. All I want to do is transmit AM from one USRP to another, which I thought would be the simplest RX/TX chain I could come up with for a start.
However, I have not managed to get a clean AM reception with a USRP. I'm pretty sure the tx component works, because I can listen to my transmission with an old kitchen radio and it sounds fine. RXing with the USRP simply doesn't work, though, neither with usrp_rx_nogui.py nor with anything I could come up with. I get lots more noise than expected and usually I get a very loud buzz or whistle which is a lot louder than the TXed signal. Has anyone else had this problem? I'm using the Basic* boards directly connected to an antenna (no bandpass filtering). I realize this is not how the BasicRX is intended to be used, but can this be the cause of a loud buzz or would it only create lots of extra noise? Basically, is this a completely futile attempt? I also tried the TVRX and then I sometimes get some spectral lines around 40kHz next to my main signal (this frequency doesn't occur anywhere in my RX chain, it's audio at 32kS/s interpolated to 320kS/s for the USRP). My filters on the TX chain seem OK, at least I haven't seen those spectral lines on an (external) spectrum analyzer. Has anyone else ever seen lines like this? Thanks for any help, -- Martin Braun Institut fuer Nachrichtentechnik Universitaet Karlsruhe http://www.int.uni-karlsruhe.de _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
