[USRP-users] B200 cannot output a sine wave

Aaron Smith aarsmith54 at gmail.com
Mon Jul 27 22:31:37 EDT 2020


Marcus,

I have tried frequencies ranging from 75-450 MHz. My scope is good to 500
MHz. I have tried gain settings betweeb 30 and 60. I am using RG-174, which
is good to 1000 MHz.

In my custom code I generate tones by sending repeating samples with a
value of 0.8. In the past this caused tones to appear at B200's center
frequency. This should work regardless of the clock rate or sample rate,
but in this case I'm using a 48 MHz master clock rate and a sample rate of
8 MHz.

I also followed a gnuradio companion tutorial to generate a tone and it
produced something ugly too.

The only thing in my setup that changed is the host laptop. I switched to a
new laptop and had to build UHD from scratch. However, gnuradio companion
appears to use a different UHD version, so I'm skeptical that is the
problem.

Thanks for your help.

On Mon, Jul 27, 2020, 7:45 PM Marcus D. Leech via USRP-users <
usrp-users at lists.ettus.com> wrote:

> On 07/27/2020 09:05 PM, Aaron Smith via USRP-users wrote:
>
> Hello all,
>
> I am trying to output a sine wave from a B200 using custom code, or the
> UHD tx_waveform example. In either case, when I view the output on an
> o-scope, there is not a pure sine wave. The output looks more triangular
> wave. I have used this scope with other B200s and the same code to get a
> pure sine. Is the radio damaged? Is there some sort of calibration
> required? I am using UHD 3.15.0.
>
> Thanks
>
>
>
> _______________________________________________
> USRP-users mailing listUSRP-users at lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
> What frequency?  What gain settings? What is your baseband bandwidth?  Is
> your coax cable known to be "good" at the frequency of interest?
>   What sample rate?  Is the baseband signal well within the Nyquist limits?
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
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