The automatic setting of the master clock seems to be getting in the way
after the PPS transition. Try explicitly setting the master clock.
"num_recv_frames=128,master_clock_rate=" + str(samp_rate*4)
Ron
On 11/19/20 03:33, Josh via USRP-users wrote:
Marcus,
This is naked hardware - B210 usb into a pretty beefy laptop running
Ubuntu 20.04, GNU Radio latest master (3.9)
Even with num_recv_frames = 128, still getting "ODD" at startup of the
flowgraph
Any other optimizations I should be tuning? Getting no overruns in
the steady state, just at startup.
Flowgraph is attached.
Josh
On Wed, Nov 18, 2020 at 4:46 PM Marcus D. Leech via USRP-users
<usrp-users@lists.ettus.com <mailto:usrp-users@lists.ettus.com>> wrote:
On 11/18/2020 07:27 AM, Josh via USRP-users wrote:
I'm seeing a difference in behavior between gr-uhd and plain uhd
c++ api:
Setup:
B210, 2 channels, 5MSPS, master_clock_rate 20MSPS, PPS sync
Receive only flowgraph
With gr-uhd, there is always a "OOD" when the flowgraph first starts
But, if I replicate the setup in a simple compiled program using
the uhd API with all the same settings, this never occurs.
So my question is - is the GR scheduler doing something at the
beginning of the flowgraph that delays the work() calls and
causes overflows, and are there settings I use to mitigate this?
My problem is that once these overflows occur, I can't trust my
timing synchronization on the received samples (or have to do
further calculations on the rx_time tags).
Thanks,
Josh
_______________________________________________
Try specifying "num_recv_frames=128" in your device arguments.
Also, are you running this on naked hardware or through a VM?
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