On Thu, Jun 23, 2011 at 7:21 PM, Colby Boyer
<address@hidden> wrote:
On Thu, Jun 23, 2011 at 4:11 PM, Nick Foster
<address@hidden> wrote:
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> Where should I look for the API to tag samples on the USRP?
Tagging in this case has nothing to do with the USRP and everything to
do with Gnuradio. Take a look at the burst_tagger in
gnuradio-core/src/lib/general/gr_burst_tagger.cc for an example.
The Mode S decoder I wrote also uses tags throughout for preamble
tagging and framing, and can be found at
git://github.com/bistromath/gr-air-modes.git.
--n
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> --Colby
I think it does have something to do with the USRP. I need to know at what time my TX sampled got processed by the USRP, as this is the trigger for an RX burst.
--Colby
At one point, we looked into outfitting the UHD source block to read the packet metadata from the USRPs and send a tag when we saw a new time stamp. We took it out for efficiency reasons, but I think you could make another class like gr-uhd/lib/gr_uhd_source_tagged or something like that. Look at the metadata in the UHD packets, see if the timestamp is valid (there's a flag for that), and then you can extract the time and make it a new tag.
Tom