Re: [Discuss-gnuradio] Unwanted signal transmitted RFX900

[Nick Foster]

On Thu, 2011-01-20 at 12:48 +0100, Paco Quiñoy wrote:
> 
> Hi all,
> 
> Making some tests I have found that my system (USRP + RFX900)
> transmits an important signal (it seems a tone) without any
> application running, just when I plug the power source it transmits
> this unwanted signal. I'm working at the GSM900 downlink frequency
> band (between 935 and 960 MHz) and the signal appears close to the
> upper side of this band, around 959,6 Mhz. 
> 
> My system makes an spectrum sensing for that band and it locates the
> present signals, so it produces an error because it detects this
> undesired signal generated by itself. Any idea of the problem? Any
> solution?

Paco,

This is likely to be the 15th harmonic of the USRP's 64MHz sample clock
(64e6*15=960e6). It may get better after the USRP is initialized (run
uhd_usrp_probe or any other application after power-up). The AD9862
tends to come up in a weird state.

--n

> 
> Thanks!
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