Ok lets explain a little bit more what actually you observe. Each
burst is a training sequence that has a duration of 64 samples and
then 1000 zero samples. This is generated using a vector source
block repeatedly. As you can see in the ok.jpeg all sequences are
exactly the same. In the other plot however the sequence
constantly changes. To me, it seems that parts of the actual
sequence are randomly cropped or re-arranged. This happens only
when two different B210 are used. We also tried to transmit the
sequence from a third device with the same results.
And yes we have tried to receive from both devices each one
working on a separate flowgraph. The result was exactly the same.
I'm having a hard time seeing a significant functional
difference between the two. Could you perhaps explain?
Also, maybe a diagram showing the two configurations?
Do you get any error messages during a run?
Are you doing reception on the two USRPs within a single
flow-graph, or two separate processes?
On 2017-06-13 10:51, Manolis Surligas wrote:
Hi Marcus,
yeah we have updated the UHD on the latest version and the
problem still persists. I have started to debug the UHD and we
suspect some kind of inconsistency between the device pointers
of the different devices. Perhaps a race condition is hidden
somewhere.
I also attach two plots. The first one is the problematic
with two different USRPs and the second the expected signal
transmitting and receiving using the same USRP.
Thanks, George.
Two things:
Could you try updating to the most recent UHD version?
It would be helpful if you provided your .dat files in the
form of plots or graphs, highlighting the areas you consider
"distortion". This will help us help you.
On 2017-06-13 07:23, George Vardakis wrote:
Good evening,
I attach three captures to show you the problem, one
with the reference signal i transmit, one with the
received samples when using the same device for TX and
RX and one with the received samples of the one device,
when the second one transmits. I also attach the
flowgraph i used for this capture. The sampling rate i
use is 1MHz. The specific captures are done with the
USRPs over USB-2 ports, but i have also tried over USB-3
and observed the same behavior.
Thank you for your time
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