Re: [Discuss-gnuradio] USRP S-Band RX

[CEL]

The equidistant spurs do really indicate RX overloading.

Overloading lead to the amplifier being non-linear. Non-linearity leads
to intermodulation, intermodulation leads to equidistant spurs.

Please add attenuation; you don't want to damage your receiver, right?

Best regards,
Marcus

On Mon, 2018-07-16 at 21:16 -0400, Justin Shetty wrote:
> This is through a cable, but without the amplifier activated. It looks 
> identical over the air though.
> 
> On Mon, Jul 16, 2018 at 5:57 PM Marcus D. Leech <address@hidden> wrote:
> > My guess would be that the RX is ovkerloaded. Is this via cable? If so do 
> > you have plenty of attenuation inline?
> > 
> > Sent from my iPhone
> > 
> > On Jul 16, 2018, at 5:29 PM, Justin Shetty <address@hidden> wrote:
> > 
> > > Hi all,
> > > 
> > > I am working with an s-band radio and am receiving its OQPSK-modulated 
> > > signal on an USRP N210. The signal I'm seeing on an FFT and constellation 
> > > plot before any processing are not as expected though. It is very 
> > > different from the example shown in the GNU Radio tutorial 7 (random 
> > > source to a constellation modulator to a channel model). I also looked at 
> > > the signal on a spectrum analyzer and it did not show the repeated peaks 
> > > I am seeing on my FFT. Does anyone know where I might be going wrong or 
> > > what's happening?
> > > 
> > > Justin Shetty
> > > 
> > > <fft_and_constellation.PNG>
> > > _______________________________________________
> > > Discuss-gnuradio mailing list
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> > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> 
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