Getting IQ data from 2 uspr1 synchronously

GNU Radio
1

HI all,

I need to get IQ samples from 2 USRP1 in a synchronous manner.

Thus I cant make:

urx1->read()
urx2->read()

I’need to execute the two “read()” operation “at the same time” (or
something similar).

Any suggestion to do that ?

Thanks in advance
Luca

2

I’m not aware of an existing way to do this on the USRP1. A function
similar to the USRP2 pps input (and start_streaming_at or at least
inband timestamps) would be required. In addition to a shared clock of
course.

Perhaps this would make a good addition for a future inband FPGA
revision. Is anyone else interested in such a feature?

–ETS

3

Check out the usrp_multi code - I believe it all got updated to work
with the hier_block2 API update. It’s in
gnuradio-examples/python/multi_usrp, and it comes with a custom FPGA
image (pre-inband signaling - the timestamps get interleaved with the
data, and the data gets de-interleaved and ordered correctly on the
host. One USRP provides a master clock that the second slaves to - via
an SMA connector you’ll have to solder in (in addition, two pins on the
daugherboard interface are used to send a ‘start’ pulse, similar to the
1pps function on the USRP2).
I haven’t messed with it in a while, but it worked when I last tried it
out.
Doug

urx2->read()

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–
Douglas G.
Code 5545
U.S. Naval Research Laboratory
Washington, DC 20375
(202) 767-9048
[email protected]