Hi, all!
I am working on a proof of concept of a radar system for my doctoral
thesis. I recently installed the great gr-pdu and gr-timing
utilities from Sandia Labs and I am trying to develop a little
application with GNURadio Companion (GRC), based on a USRP N200
system.
I essentially want to use the rising edges of a pulsed signal to
generate another signal. For this purpose, first the trigger signal
is sampled with a USRP-Source block, then is threshold detected by
means of a "Threshold trigger" block and finally, a message with a
"Tag message trigger" block is generated. The output of this last
block feeds a "PDU to Bursts" block which enters a USRP-Sink.
I have checked with a "Tag Debug" that the threshold detection and
message generation are both working fine. At the output of the "PDU
to Bursts" block, each burst is tagged with the "tx_sob" and
"tx_eob" tags. The problem arises when those burts enter the
USRP-Sink. As far as I've read, this blocks transmits all burts
sequentially ignoring the time separation that should be between
them. Please, take into account that the trigger pulses are not
equally separated in time, so I must transmit one burst with each
received pulse.
I think the issue is that no "tx_time" tags are being generated and
added to each burst. I wonder if anyone have the same explanation
for this issue, and hopefully, if anyone can guide me on how can I
inject those "tx_time" tags properly in my stream with GRC.
Any help will be appreciated!
Regards,
José