On 2021-12-10 17:25, isaac mario tupac davila wrote:
Hello everyone!
My name is Isaac. I have a curious situation here... I've generated a
pulsed signal per second. I've saved one second period in a .h5 file,
so that I'm sure I'm having a fixed signal per second, and then repeat
it in my GRC flowgraph. .
To use this signal as Tx I'm trying to synchronize a USRP N200 and a
trimble in GRC. After run my flowgraph, this is what I see:
imagen.png
imagen.png
The yellow signals are the PPS of my trimble and my purple signals are
my tx signal per second. They are periodic in time but when you see it
deeper, the difference between the timble PPS and my Tx signal is
approx 97 ms. I think this difference should be close to cero, as my
USRP and trimble are synchronized. ¿What is happening here? ¿Is this a
normal behavior? I'm using unknown PPS to configure my UHD:USRP sink
in GRC....
I'll appreciate any help to clarify this behavior
Regards
Isaac T.
Your flow-graph made very little sense to me. If you want to
synchronize your TX, you have to take explicit measures to ASK the USRP
to schedule your transmits at specific times.
The 1PPS signal only synchronizes an internal time-stamp clock in the
unit. It has NO WAY of knowing what the *meaning* of your samples are,
so it can't possibly
synchronize some arbitrary event in your continuous sample stream to
1PPS without you explicitly asking for when your bursts need to be sent.
https://kb.ettus.com/Synchronizing_USRP_Events_Using_Timed_Commands_in_UHD
