It could be the usrp digitally clipping, not the analyzer. Matt
On Tue, Jan 7, 2014 at 5:17 PM, Jonathan Fox <[email protected]>wrote: > On Tue, Jan 7, 2014 at 7:11 PM, Marcus D. Leech <[email protected]> wrote: > >> >> Try reducing the amplitude to 0.7. Another possibility is that your >> computer can't keep up. If you are using one of the standard programs, are >> there U's printing in the terminal? >> >> Matt >> >> Also, what RF gain are you setting? Does it exceed the maximum input >> level of the spectrum analyser? >> >> Are you connected directly, or with an antenna? >> >> >> >> On Tue, Jan 7, 2014 at 3:03 PM, Jonathan Fox >> <[email protected]>wrote: >> >>> A colleague and I are sending a simple signal in GNU Radio (sine wave, >>> 1 MHz, amplitude of 1) to the USRP sink and have the center frequency at >>> 500 MHz. The N210 USRP is hooked up to an Agilent spectrum analyzer. On the >>> analyzer we are seeing a weird phenomena every two seconds. At first we see >>> the carrier frequency and two sidebands from the sine wave (see attached >>> normal.gif). Then after two seconds we get two bursts of multiple harmonics >>> (see odd.gif). >>> >>> The question is, why is this happening? Does the phase of the 1 >>> KHz signal become discontinuous before or after being sent to the USRP? >>> >>> Thanks, >>> >>> Jon Fox >>> >>> _______________________________________________ >>> USRP-users mailing list >>> [email protected] >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >>> >> >> _______________________________________________ >> Discuss-gnuradio mailing >> [email protected]https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> >> >> -- >> Marcus Leech >> Principal Investigator >> Shirleys Bay Radio Astronomy Consortiumhttp://www.sbrac.org >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> [email protected] >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> > > > I don't recall seeing any U's but I can recheck tomorrow. The gain on the > USRP was set to -2. The USRP was connected directly with an SMA cable. The > analyzer is an Agilent E4440A, the Analyzer is rated for at least 1 Watt on > average, 100 Watt on a peak pulse (with the built-in attenuator in use). > While I am not ruling out the maximum input I thought the N210 tops out at > 0.5 Watts due to FCC regulations. > > Thanks > > Jon > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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