[USRP-users] Possible Causes of This Spurious Signal?

Marcus Müller marcus.mueller at ettus.com
Wed Jul 26 16:07:41 EDT 2017


Hello Kyeong Su Shin,

what's the RF power reaching the USRP? Does this get better when you
reduce the RX gain or the TX power?

Best regards,

Marcus


On 26.07.2017 16:52, Kyeong Su Shin via USRP-users wrote:
> Hello,
>
> I observe a spurious signal in the PSD estimates that are obtained
> using a USRP, which I cannot identify the cause. Could someone help me
> identifying the cause of this?
>
> Plots are shown below.
>
> _Hardware_:
> -USRP N200 r4 + UBX-40 v1
> -Agilent FieldFox SA, as the reference.
>
> _Software_:
> -Windows Server 2012
> -UHD 3.9.3
> -GNURadio 3.7.10.1
>
> ..and also on a UHD-based (non-GNU Radio) spectrum scanner script that
> I am working on.
>
> _Setting_:
> Gain : 0
> lo offset : 0
> Samp rate : 25MS/s (100e6/4)
> Antenna: RX2
>
> _The Spurious Signal:_
>
> @ fc = 641.25 MHz (reproducible at 642 / 641 MHz)
>
>> Goes away @ fc = 630MHz.
>
>> _+- 25MHz_:_
>
> _No, I don't see any signal that could get aliased; I believe this is
> not due to the aliasing from the DDC._
>
> _
>
>
>> _1/2 fc (315MHz):_ Clean (no signal observed).
>
>
>>
> Regards,
> Kyeong Su Shin
>
>
> _______________________________________________
> 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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