Ok forget, I had to remove the lo offset from the transmitter and not from the receiver! (facepalm)
There are still some minor peaks but I think I can remove them using the same proccess frankist wrote: > > Hmm, I tried to use this to change the LO offset: > self.signal_source_0.set_center_freq(uhd.tune_request(self.freq+self.freq_offset,self.lo_off)) > > However, now I have a new peak and this peak doesn't disappear when I turn > off the transmitter. > > I am using a USRP2 and XCVR2450 > > > mleech wrote: >> >> On 07/04/12 10:12 AM, frankist wrote: >>> Hi, >>> >>> I am using GNU Radio for 2 weeks. I always get in the receiver side a >>> signal >>> with a peak in the carrier frequency when I turn on the transmitter even >>> if >>> I send a signal made of zeros. You can see it in the picture >>> http://old.nabble.com/file/p33648622/usrp_carrier_peak.png >>> >>> In spite of being handy to discover the frequency offset of my signal, >>> it is >>> influencing my results when I try to measure the power of the received >>> signal. I thought this was the DC offset, but I read somewhere that >>> USRP2 >>> eliminates the DC Offset. >>> >>> So, do you know what it is and how to remove it? >>> >> This is LO leakage. What is you setup here--two USRPs with XCVR cards? >> >> Mixers always have some amount of LO leakage at the output port. >> Depending on your signal bandwidth, >> you can use an LO offset to move that leakage outside of your >> applications passband, but there'll still be >> leakage--just not at a place that matters to you. >> >> -- >> Principal Investigator >> Shirleys Bay Radio Astronomy Consortium >> http://www.sbrac.org >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> > > -- View this message in context: http://old.nabble.com/USRP-inserts-a-peak-in-the-carrier-frequency-tp33648622p33648955.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
