[USRP-users] UBX synchronization

Piotr Krysik perper at o2.pl
Sat Oct 17 11:53:12 EDT 2015


Hi all,

The changelog of UD 3.8.3 mentions this:
* UBX: Fixed phase synchronization issues 	(Related changes: Change X300
daughterboard frequency, increase 	N210 FIFO depth)


Does it mean that phase synchronization of multiple UBX daughter-boards
is officially supported since that version?

Best Regards,
Piotr Krysik

W dniu 05.03.2015 o 00:52, Michael West via USRP-users pisze:
> Hi Brandon,
>
> The UBX uses the MAX2871 synthesizer which has a phase resync feature
> by means of configuring the MUX pin and asserting a rising edge on
> it.  This is unlike the ADF4351 synthesizer which has the resync
> feature built-in and automatically resynchronizes the phase after
> tuning.  Because of that, the phase resync feature for the UBX is
> actually still in development and we plan to have it available in UHD
> 3.8.3.  Once available, it will offer the same level of phase
> synchronization as the SBX board.  That means that the relative phase
> offset should remain consistent across tunings and power cycles, so
> phase calibration should become much simpler.
>
> Regards,
> Michael E. West
>
> On Wed, Mar 4, 2015 at 12:27 PM, Cochenour, Brandon M CIV NAWCAD,
> 4.5.6 via USRP-users <usrp-users at lists.ettus.com
> <mailto:usrp-users at lists.ettus.com>> wrote:
>
>     Yes, I assumed they were all sharing the same reference and
>     coherent, but it was the "alignment" part that maybe suggested a
>     way to tune/do phase resync/etc..  Maybe I'm reading too much into
>     it.  http://www.ettus.com/content/files/UBX_Spec_Sheet.pdf
>
>
>     It's always a bit of a pain with the WBX to have the ambiguity
>     between Tx and Rx...or the unknown phase difference between radios
>     even if all phase locked to a common reference.  Was hoping that
>     the UBX was going to eliminate a bunch of extra calibration
>     procedures...
>
>
>
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>
>
>
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