Hi all, I'm analyzing the B200 and I found out that the frequency response have some high power spurs. In annex I'm sending an example. In this example the data was gather at a Fc=161MHz, Fa=(5+1/3)MHz with a 36.5 gain and with the B200 closed at a Faraday cage with no external sources of noise and with the connected laptop covered in aluminium. In this situation there's a visible spur at 160MHz, does someone knows what the source may be? Best Regards, Daniel Malafaia

Hi Daniel, It could be a harmonic of the master clock. The default master clock rate is 32 MHz and 5x32=160. Try setting the master clock rate to a different value to see if it changes. Regards, Michael E. West On Sat, Oct 25, 2014 at 2:13 PM, Daniel Malafaia via USRP-users < usrp-users@lists.ettus.com> wrote: > Hi all, > > I'm analyzing the B200 and I found out that the frequency response have > some high power spurs. > In annex I'm sending an example. In this example the data was gather at a > Fc=161MHz, Fa=(5+1/3)MHz with a 36.5 gain and with the B200 closed at a > Faraday cage with no external sources of noise and with the connected > laptop covered in aluminium. > In this situation there's a visible spur at 160MHz, does someone knows > what the source may be? > > Best Regards, > Daniel Malafaia > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > >

Dear Michael, that was spot on, there's harmonics in multiples of the master clock at 32 MHz. Also I found out that at the same time it also happens at 40MHz multiples, what would be the source of that? Best Regards, Daniel Malafaia 2014-10-27 19:54 GMT+00:00 Michael West <michael.west@ettus.com>: > Hi Daniel, > > It could be a harmonic of the master clock. The default master clock rate > is 32 MHz and 5x32=160. Try setting the master clock rate to a different > value to see if it changes. > > Regards, > Michael E. West > > On Sat, Oct 25, 2014 at 2:13 PM, Daniel Malafaia via USRP-users < > usrp-users@lists.ettus.com> wrote: > >> Hi all, >> >> I'm analyzing the B200 and I found out that the frequency response have >> some high power spurs. >> In annex I'm sending an example. In this example the data was gather at >> a Fc=161MHz, Fa=(5+1/3)MHz with a 36.5 gain and with the B200 closed at a >> Faraday cage with no external sources of noise and with the connected >> laptop covered in aluminium. >> In this situation there's a visible spur at 160MHz, does someone knows >> what the source may be? >> >> Best Regards, >> Daniel Malafaia >> >> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> >> >

Hi Daniel, I honestly have no idea what could be causing harmonics every 40MHz unless the master clock rate was changed to that value. Regards, Michael On Wed, Oct 29, 2014 at 11:01 AM, Daniel Malafaia <dmalafaia@gmail.com> wrote: > Dear Michael, > > that was spot on, there's harmonics in multiples of the master clock at > 32 MHz. Also I found out that at the same time it also happens at 40MHz > multiples, what would be the source of that? > > Best Regards, > Daniel Malafaia > > 2014-10-27 19:54 GMT+00:00 Michael West <michael.west@ettus.com>: > >> Hi Daniel, >> >> It could be a harmonic of the master clock. The default master clock >> rate is 32 MHz and 5x32=160. Try setting the master clock rate to a >> different value to see if it changes. >> >> Regards, >> Michael E. West >> >> On Sat, Oct 25, 2014 at 2:13 PM, Daniel Malafaia via USRP-users < >> usrp-users@lists.ettus.com> wrote: >> >>> Hi all, >>> >>> I'm analyzing the B200 and I found out that the frequency response have >>> some high power spurs. >>> In annex I'm sending an example. In this example the data was gather at >>> a Fc=161MHz, Fa=(5+1/3)MHz with a 36.5 gain and with the B200 closed at a >>> Faraday cage with no external sources of noise and with the connected >>> laptop covered in aluminium. >>> In this situation there's a visible spur at 160MHz, does someone knows >>> what the source may be? >>> >>> Best Regards, >>> Daniel Malafaia >>> >>> >>> _______________________________________________ >>> USRP-users mailing list >>> USRP-users@lists.ettus.com >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >>> >> >

B200 uses a 40MHz oscillator on the PCB to derive all frequencies used in the radio. -Ian On Oct 29, 2014, at 7:08 PM, Michael West via USRP-users <usrp-users@lists.ettus.com> wrote: > Hi Daniel, > > I honestly have no idea what could be causing harmonics every 40MHz unless the master clock rate was changed to that value. > > Regards, > Michael > > On Wed, Oct 29, 2014 at 11:01 AM, Daniel Malafaia <dmalafaia@gmail.com> wrote: > Dear Michael, > > that was spot on, there's harmonics in multiples of the master clock at 32 MHz. Also I found out that at the same time it also happens at 40MHz multiples, what would be the source of that? > > Best Regards, > Daniel Malafaia > > > 2014-10-27 19:54 GMT+00:00 Michael West <michael.west@ettus.com>: > Hi Daniel, > > It could be a harmonic of the master clock. The default master clock rate is 32 MHz and 5x32=160. Try setting the master clock rate to a different value to see if it changes. > > Regards, > Michael E. West > > On Sat, Oct 25, 2014 at 2:13 PM, Daniel Malafaia via USRP-users <usrp-users@lists.ettus.com> wrote: > Hi all, > > I'm analyzing the B200 and I found out that the frequency response have some high power spurs. > In annex I'm sending an example. In this example the data was gather at a Fc=161MHz, Fa=(5+1/3)MHz with a 36.5 gain and with the B200 closed at a Faraday cage with no external sources of noise and with the connected laptop covered in aluminium. > In this situation there's a visible spur at 160MHz, does someone knows what the source may be? > > Best Regards, > Daniel Malafaia > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com