Re: Inject "tx_time" tags in a stream

Has anyone worked with tx_time tags?

jnunez@uvigo.es escribió:

> 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