Hi,
I have very similar problem with X310. I am running a C++ application,
so I have a bit more flexibility I guess. After I do the
set_time_unknown_pps to sync to the 1PPS signal, I run the function
get_time_last_pps and it sometimes has an offset of 10ns (it was 5ns for
an old firmware due to a bug, which was fixed a few weeks ago). If that
is the case I just do the sync again until the offset is zero.
I don't know if it is an firmawre problem or if it is because the signal
integrety of the 1PPS signal is not good enough.
Maybe that is also a solution for you.
Best regards,
Fabian
Am 25.09.2019 um 11:16 schrieb Cherif Diouf via USRP-users:
Hello,
I am working with the X310 USRP. I have two identical custom blocks
feeding the RF frontends.
flowchart
-----------------
HW Block1 -> RF0-TX1 |---<
HW Block2 -> RF1-TX1 |---<
The system is synchronized to an external PPS reference. The sampling
rate is 200 MSps and the signal bandwidth is 160 MHz for both channels.
The two HW blocks start transmitting at the exactly same time. Time
resolution is 5ns.
In most cases the two outgoing RF signals present a 1ns time offset.
Which can be understood as a phase offset.
But From time to time there is a 6ns delay between the channels. I
assume this 6ns comprises the 1ns delay due to phase offset + 5 ns delay
due to misalignment of outgoing samples.
What could be the origin of this one sample misalignement? Is it a way
to fix it? Or working close to the limits of the device should such
behavior be expected?
Thanks in advance
Best Regards
Cherif
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--
--------------------------------------------------
M.-Sc. Fabian Schwartau
Technische Universität Braunschweig
Institut für Hochfrequenztechnik
Schleinitzstr. 22
38106 Braunschweig
Germany
Tel.: +49-(0)531-391-2017
Fax: +49-(0)531-391-2045
Email: fabian.schwar...@ihf.tu-bs.de
WWW: http://www.tu-braunschweig.de/ihf
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