We are testing 2 USRP N210 units with data gathering (using GRC source
file sink). The command from the host to the N210 is sent at the
approximately simultaneous time (referenced to system NTP time).
the samples gathered from the 2 units appear to differ by as much as
seconds! The intention is to gather data at the 2 units at approximately
same time as the pre-programmed system time commands. The gathering is
with the top_block.py code generated from GRC. What happens inside the
appears to be beyond my control here. So the natural thing to do here is
time-stamp the samples with host computer system time. I hope that we
have to use an external reference for the USRP. Isn’t there an internal
clock that is continuously counting. If we can get the USRP clock counts
tie together the samples counts and the host computer system time, we
be in good shape. Is this a good idea?
Your thoughts and help are appreciated.