Burst Tagger block - What I'm I doing wrong?

Hi all!

Im trying to implement a system that should change it’s normal
when another system with higher priority comes into play. For that, we
thought of two ways: changing the central frequency of our system of
interest and/or stopping the sending process automaticaly.

Im in charge of the latter, and for that I’ve found that maybe the
tagger” block could be of use. As far as I have understood, that block
SOB and EOB tags to the element that I’m about to send, and those are
understood in the UHD as metadata. Afterwards (and may be here is where
get a little bit confused or have the misconception of its
‘if the UHD receives an EOB tag, it turns of the transmitter until a new
SOB comes’. (I would also like to know if the part in between the
quotation marks is also right. I’ve checked the code for UHD sink and I
still dont have this part 100% clear).

Now, comes my main question and the reason why I think Im getting the
concept wrong: I apply a signal (sinus) at the first port of the burst
tagger and on the second I apply what would be my detection of the other
system. In order to see if the tags come or not, I connect at the output
the block a “Tag debug”, where I do can see that it is a ‘False’ tag
the trigger is <=0 and ‘true’ when it is >0. However, I still see the
signal being sent through the USRP.

I dont know if the sinus signal is not suitable for this test
or if actually the burst tagger does not do what I understood. If
has a clearifying opinion or remark I would really appreciate it. I’ve
checked some previous questions here in feeder and the example
was implemented as I did. Any comment will be highy welcomed.

Thank you in advance.



On Thu, Apr 16, 2015 at 12:05 PM, Nicolas Cuervo B. <
[email protected]> wrote:

understood in the UHD as metadata. Afterwards (and may be here is where I
the block a “Tag debug”, where I do can see that it is a ‘False’ tag when



I think the issue is related to the fact that the gr-uhd and that
burst_tagger weren’t designed together. In fact, the burst tagger block
came before the UHD blocks handled tags and there wasn’t any

First, place a tag_debug block in the flowgraph after the burst_tagger.
That will make sure that the burst_tagger is actually properly tagging

But the main problem is that the burst_tagger produces tags with the key
“burst” and the value true or false. You’ll need to edit this block to
change it to using “tx_sob” for the start of burst and “tx_eob” for the
end. That should get you closer to what you want.