On 2022-01-24 12:37, Ming You wrote:
Hi Marcus,
The X310 is actually fulfilled by USRP-2950, i.e., X310 and WBX and GPSDO.
The graph has been attached, actually it is very simple, just send a triangle signal over
one channels from the tx (for convenience, I've only attached one antenna to the one
channel on tx side, so that it is a much clear constellation figure on rx side). The
constellation for such case should be a quadrilateral shape. With X310(WBX), the
constellation at both channels at rx is very robust (the shape is not moving much), but
with N321, the constellation shape is apparently rotating with time, and if increasing
frequency it might just rotate. That is what I am confused about the N321 phase lock
performance even with external REF and PPS from CDA 2990. It seems to me that there
should be some "proper" configuration/tuning, if this is not a bug.
Regarding the 3rd question on what I am measuring, from the above description
you can get an idea what I mean -- I just want the N321 to have the same phase
performance as X310, since the robust phase locking is critical to any
experiment when multiple channels/usrps are involved.
Also to mention that I've tried all supported N321 master clock, 200M, 245.76M
and 250M, they don't help and problems are the same.
Any idea or suggestions will be much appreciated.
Thanks,
Ming
What happens if you reduce the baseband amplitude a little -- perhaps
to 0.85 or 0.9?
Are transmitting over cable or antennas? If cable, do you have an
attenuator in place? If so, how much attenuation?
Are you able to confirm that the CDA-2990 is producing a 10MHz and 1PPS
signal?
_______________________________________________
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-le...@lists.ettus.com
