Hi, This is a problem I have been having for a while, but I've never given it enough importance until now.
Basically I have a USRP2 as a receiver and no transmitter. So basically, I am just measuring noise. I am using the 5GHz band. Here are the fft plots for freq. 5GHz and gain 30 and 50. http://old.nabble.com/file/p33690634/pic1.jpg http://old.nabble.com/file/p33690634/pic2.jpg As you can see the peak at center frequency is eliminated by changing the gain. So I guess it was just some DC offset that wasn't removed by the USRP. However, the other peak at -30kHz approximately remains. I tried to use uhd.tune_request thinking it was some leakage but the peak doesn't move. When I use a center freq. greater than 5GHz and lesser than 5.5GHz I get this: http://old.nabble.com/file/p33690634/pic3.jpg http://old.nabble.com/file/p33690634/pic4.jpg In this case I have a peak at center frequency which isn't attenuated even if I change the gain. The peak at -30kHz remains also. I tried using the uhd.tune_request treating these peaks as leakage but they didn't move at all once more. At 5.5GHz, I don't have any peak (I don't think it is necessary to post a image in this case) except for a small DC offset which is eliminated with a increase in the gain. The peak at the center frequency (but not the -30kHz peak), however, appears again for frequencies greater than 5.5GHz but less than 6 GHz. Someone answered me in another post about the leakage problem and how to solve it. However, those tools are not working in this case. -- View this message in context: http://old.nabble.com/Problems-with-DC-offsets%2C-leakage-and-other-stuff-tp33690634p33690634.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
