[USRP-users] GPSDO Support

John Malsbury john.malsbury at ettus.com
Mon Jun 4 11:57:42 EDT 2012


Simon,

If you follow the instructions here, and burn the EEPROM, the USRP will 
be configured to select the GPSDO 10 MHz and 1 PPS by default.  As 
indicated in the installation instructions provided with the GPSDO, you 
will have to move a jumper that will connect the GPSDO 10 MHz, and 
disconnect the external 10 MHz reference.  You should not need to do 
anything with the .hdl code.

Have I properly understood your questions?

-John

On 6/3/2012 2:39 PM, Simon HB9DRV wrote:
>
> Hi Marcus,
>
> Thanks -- it's the internal GPSDO I'll be using. The oscillator phase 
> noise is very good.
>
> Simon Brown, HB9DRV
> http://dit-dit-dit.com <http://dit-dit-dit.com/>
>
> You are standing at the end of a road before a small brick building. 
> Around you is a forest.
>
> A small stream flows out of the building and down a gully. The sunspot 
> count is 285.
>
> *From:*Marcus D. Leech [mailto:mleech at ripnet.com]
> *Sent:* 03 June 2012 18:37
> *To:* Simon HB9DRV
> *Cc:* usrp-users at lists.ettus.com
> *Subject:* Re: [USRP-users] GPSDO Support
>
>     Hi,
>
>     Via UHD.dll or flipping switches? It looks like I'll be buying one
>     anyway, the phase noise spec is very good.
>
>     Searching the UHD.dl source code I see this which indicates that
>     it's used automagically:
>
>     "By default, if a GPSDO is detected at startup, the USRP will be
>     configured to use it as a frequency and time reference. The
>     internal VITA timestamp will be initialized to the GPS time, and
>     the internal oscillator will be phase-locked to the 10MHz GPSDO
>     reference. If the GPSDO is not locked to satellites, the VITA time
>     will not be initialized."
>
> That is only, as far as I know, for the "in skin" internal GPSDO.
>
>
>
>
> -- 
> Marcus Leech
> Principal Investigator
> Shirleys Bay Radio Astronomy Consortium
> http://www.sbrac.org
>
>
> _______________________________________________
> 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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