On 2022-02-23 07:42, Alvaro Pendas Recondo wrote:
I finally managed to make it work by setting both blocks with "No
sync" (in my first scheme one of them was configured with
"Unknown PPS" by accident). There is still the problem with the
decrease of the maximum sampling rate when doing MIMO with B210.
Anyway, in this case I was just doing a simple characterization of the
devices, so I will keep in mind that some problems may appear when
synchronizing multiple B2xx externally. I am also aware that N210 is
the model recommended for that.
Thank you very much for your help.
The decrease in maximum sample rate when using two channels has to do
with the way data are clocked out of the AD9361 RFFE chip, and is a
design limitation of that chip.
El mar, 22 feb 2022 a las 20:10, Marcus D. Leech
(<[email protected]>) escribió:
On 2022-02-22 12:05, Alvaro Pendas Recondo wrote:
> Yes, I am aware of the 4-channel, but I just forget about it when
> doing comparison. The explanation behind is that I only have 3
> antennas right now, so I am actually working with 3 Rx.
> About setting Sync to "Unknown PPS", I had tried before, with no
> result, but I have setted again. However, I have never tried to
modify
> the "start time", which in GNU Radio is -1.0 by default. The
> interesting thing is that if I try to set a positive value I get
the error
> gr::log :WARN: usrp_source1 - USRP Source Block caught rx error:
> ERROR_CODE_LATE_COMMAND
>
Yeah, this is going to require a bit of custom coding on your part to
make sure that both B210 agree on what time it is when the PPS
arrives.
I think that having
*both* of them set to "Unknown PPS" won't work very well,
because the
first one will *wait* before the code even gets to the second one, so
they'll be in disagreement
about timing.
You'll likely have to do the PPS synchronization "dance" yourself.
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