I have seen the same issue in the last couple of days. My setup: Ubuntu 10.04 laptop UHD + GNUradio 3.3 USRP2 with WBX
TX parameters: 15dB gain, 1090MHz center frequency 4MS/s transmission RX parameters: 25dB gain, 1090MHz center frequency 4MS/s acquisition transmitted signal: U(t) = 10mV + 5mV * sin(2*pi*f*t) f = 100 kHz I observe unexpected sinusoidal oscillations in the amplitude at about 400kHz Oscillation amplitude is on the order of 1mV. Dave Aleš Povalač wrote: > > Dear all, > > I have been testing USRP2 with WBX board (#957). Using GNU Radio, I > have created a simple CW TX system. The problem: output signal is > oscillating when I set the TX frequencies to 900MHz band. Signal > output (in time domain) at TX/RX connector from the FSL analyzer is in > the attachment. > > Settings: > 868 MHz, 200 kSps, gain 15 dB > > Same results with: > ./tx_waveforms --rate 250000 --freq 868000000 --gain 15 > > The oscillation with ca. 1dB amplitude is present for almost all gain > settings except the lowest values. I have observed the problem at > several frequencies from 700M to 1G, sometimes with amplitude over > 2dB. > > Any ideas about the cause of this problem? Some PA instability or AGC > loop issue? > > Thanks, > Ales > > > _______________________________________________ > 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/WBX-CW-transmit-problem-tp31963722p31964536.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
