Ok, great. I am trying to think of ways to now add the phase measurement. Ideas...
- In order to get consistent phase, you would need to tune Rx and Tx DSP at the same time (rather than below where you are only tuning one of them). So, assuming that this will not produce consistent phase results, then maybe try the following idea... - If you want to check just Rx DSP tuning (with fixed Tx DSP tuning), you could try a 2 channel Rx measurement where the Tx is split externally with 1:2 splitter in order to drive both Rx0 and Rx1. Then, measure the relative phase Rx0/Rx1 and then tune back and forth between two Rx DSP freqs to see if the relative phase on Rx remains constant. If so, this would give you good confidence that Rx DSP tuning is indeed happening synchronously - Assuming that the Rx IS synchronous in the step above (perhaps a bad assumption, but here goes), you could then check TX DSP tuning (with fixed Rx DSP tuning) by using two Tx and two Rx channels with Tx0 connected to Rx0 and Tx1 connected to Rx1. At this point we are confident that Rx DSP tuning is synchronous so any synchronous misbehavior would imply a Tx sync problem. Sorry I can't think of better ideas. Rob On Fri, Mar 13, 2020 at 12:12 PM Lukas Haase <lukasha...@gmx.at> wrote: > Hi Rob, > > 1.) yes, works(*) > 2.) yes, works(*) > > (*): qualitatively. I set the timed command to "get_current_time() + > uhd.time_spec(2.0)" and I see the chance 2 seconds after my click on the > screen. I cannot (do not know how) check if it actually happens at > sample-precicse location. > > Great, any ideas to simplify the setup would nice. I just don't know how I > could continue to debugging the phase. > > Best, > Luke > > > Gesendet: Freitag, 13. März 2020 um 11:08 Uhr > Von: "Rob Kossler" <rkoss...@nd.edu> > An: "Lukas Haase" <lukasha...@gmx.at> > Cc: "Marcus D Leech" <patchvonbr...@gmail.com>, " > USRP-users@lists.ettus.com" <usrp-users@lists.ettus.com> > Betreff: Re: [USRP-users] USRP X310 ignored DSP retuning on TX when using > a timed command > > Thanks Lukas, > I wanted to confirm that you did not have an older version of FPGA > firmware because there was a DDC/DUC bug fix[ > https://github.com/EttusResearch/fpga/commit/0b2364653405612a6d5dfaa0e69b1c6798771e6d] > related to phase. However, the version you provided with uhd_usrp_probe > confirms that you have the bug fix included. So, this is not the problem. > > From what you said, I assume that you can successfully do the following: > 1) with Rx tuning fixed (no re-tuning at all), tune Tx DSP only (do not > change TX RF) and you can see the frequency change at the specified command > time (i.e., if you specify the command time 1 sec in the future, the change > does not occur until 1 sec in the future). > 2) opposite of #1: with Tx tuning fixed, tune Rx DSP only and you can see > the frequency change at the specified command time. > > I am trying to simplify the issue by removing RF tuning completely and by > tuning only 1 of Rx/Tx at a time. Perhaps this will help lead to the > answer. > Rob > > > > On Fri, Mar 13, 2020 at 10:53 AM Lukas Haase <lukasha...@gmx.at[mailto: > lukasha...@gmx.at]> wrote:Hi again Rob, > > Yes, I confirm: > > 1.) Finally I get the commands to execute at the same time (TX and RX > individually and both at the same time) > 2.) Yes, the phase is random after each retune, even when I retune back to > the same frequency > 3.) (2) is only true if it includes *DSP* retuning. With naalog retuning > (+integer-N retuning) I get phase coherence, as expected. > > I actually expected the PLL retuning much more challenging than the DSP > retuning but for some reason it seems to be the opposite... > > Thanks, > Lukas > > > >
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