Used a single streamer and saw the delay slightly improve to between 2.5 - 3 ns.
Any other suggestions to improve the delay to match the results from the knowledge base, https://kb.ettus.com/USRP_N320/N321_LO_Distribution? Also, what is synchronized mode and how can I make sure that I am running in synchronized mode? Thanks for your help, Michael On Wed, May 17, 2023 at 6:26 AM Rob Kossler via USRP-users < [email protected]> wrote: > On Tue, May 16, 2023 at 8:35 PM Marcus D. Leech <[email protected]> > wrote: > > > > On 16/05/2023 20:31, Michael Toussaint wrote: > > > Hi, > > > > > > I am testing the LO synching on a single N321 using the 2 Tx channels > > > on the N321. > > > > > > I have followed the LO setup steps from the knowledge base, > > > https://kb.ettus.com/USRP_N320/N321_LO_Distribution, to distribute the > > > LO. (Sample Python code used for setup below) > > > > > > I am using separate streamers for each Tx channel and noticing a delay > > > between the 2 channels executing. > > Yeah, using separate streamers, the code doesn't attempt synchronization > > across two streamers. You'll need a single > > two-channel streamer--that's the "synchronization paradigm" that has > > been in UHD for over a decade... > > Separate streamers shouldn't be a problem. I use them regularly in > synchronized mode. If both streamers have the same time spec, the > radio should start them both in sync. That said, it won't hurt to test > with a single streamer. > > > > The Tx channels do not appear to be synchronized, we're measuring > > > anywhere from 0.5ns to 4ns of delay across the channels. > > The master clock cycle on the N321 is between 4 and 5 ns. This is > also the D/A (and A/D) clock cycle. When you are seeing a relative > delay of 0.5ns this is about one tenth of a D/A sample interval. Or, > from another perspective, this represents a difference of about 4 > inches of cable length (if the relative delay had an analog cause). > So, the channels are definitely synchronized to some degree - I don't > have a guess at why the synchronization is not tighter. > _______________________________________________ > USRP-users mailing list -- [email protected] > To unsubscribe send an email to [email protected] > -- [image: Chaos Industries] Michael Toussaint Principal Software Engineer [email protected]
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