[USRP-users] B200mini X1

Steven Knudsen ee.knud at gmail.com
Mon Mar 28 23:28:21 EDT 2016

Thanks very much for the confirmation. 

And thanks for opting for the really stable option. 

I am looking at details for holdover when 1 PPS is not available. This is relevant to TDMA systems, among other things.

An obvious question that the list or Ettus may be able to help with, and that saves me looking into the FPGA source, is whether or not the DAC setting for the VCTCXO is saved periodically while there is an external reference? I hope so :-)  I am assuming there is a simple control loop for the DAC value, guessing a PID or something.

I recently had to develop a comparable clock discipline subsystem for a radio that was being refitted with digital technologies and that would be expected to operate with or without GPS and support ranges in excess of 30 km. Loads of fun.

Thanks again for the quick response!


Steven Knudsen, Ph.D., P.Eng.
www. techconficio.ca

Der entscheidende Augenblick der menschlichen Entwicklung ist immerwährend. Darum sind die revolutionären geistigen Bewegungen, welche alles Frühere für nichtig erklären, im Recht, denn es ist noch nichts geschehen. - Franz Kafka

> On Mar 28, 2016, at 17:14, Derek Kozel <derek.kozel at ettus.com> wrote:
> Hello Steven,
> The onboard reference is a VCTCXO indeed made by CTS, you've found the right datasheet. It is the 0.5ppm version.
> Regards,
> Derek
> On Mon, Mar 28, 2016 at 3:57 PM, Steven Knudsen via USRP-users <usrp-users at lists.ettus.com <mailto:usrp-users at lists.ettus.com>> wrote:
> I may be blind, but I have not found a document reference for the clock on the B200mini. However, from the markings on the clock I think it’s a CTS VTCXO matching the link to the data sheet below. Can anyone confirm this and if so, the stability grade?
> http://www.ctscorp.com/wp-content/uploads/2015/11/008-0371-0.pdf <http://www.ctscorp.com/wp-content/uploads/2015/11/008-0371-0.pdf>
> thanks!
> steven
> Steven Knudsen, Ph.D., P.Eng.
> www. techconficio.ca <http://techconficio.ca/>
> www.linkedin.com/in/knudstevenknudsen <http://www.linkedin.com/in/knudstevenknudsen>
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> Live beyond the severed ends.  Louis MacNeice
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