[USRP-users] B200 - Spurs at the frequency domain

Ian Buckley ianb at ionconcepts.com
Thu Oct 30 01:04:13 EDT 2014


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 at 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 at 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 at 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 at 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 
> 
> 
> 
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