Re: [Discuss-gnuradio] USRP1 Clock drift

[Peter F Bradshaw]

Hi Matt;

Is it possible to include in your application a monitor which would
receive a transmission which you could use as a reference in order to
correct your transmitter's local oscillator? It seems to me that this
would be a better solution to your problem than modifying the hardware
in order to inject an external clock.

On Fri, 7 Jan 2011, Matt Robert wrote:

> Hi Guys,
>
> I ran Kalibrate against my pair of USRP1's using GSM900 towers (around
> 940MHz) and found my first unit to me 5kHz off and the second was 13kHz off.
>
> Is this within limits for the built in oscillator? I have been using
> them to transmit P25 frames around 435Mhz and found that my commercial
> P25 radios will not decode anything coming from the second USRP. The
> first USRP works OK. I have swapped around all daughterboards between
> both USRPs and the only common factor is the second USRP motherboard so
> I am sure its due to the clock in that unit.
>
> Perhaps clocktamer or a secondhand GPSDO is needed for my Tx applications.
>
> Cheers,
> Matt
>

Cheers

-- 
Peter F Bradshaw: http://www.exadios.com (public keys avaliable there).
Personal site: http://personal.exadios.com
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 keep us guessing." - Sam Kekovich.