On Fri, Jun 24, 2011 at 4:54 AM, Tom Rondeau <trondeau1...@gmail.com> wrote:
> On Thu, Jun 23, 2011 at 7:21 PM, Colby Boyer <colby.bo...@gmail.com>wrote: > >> >> >> On Thu, Jun 23, 2011 at 4:11 PM, Nick Foster <n...@ettus.com> wrote: >> >>> >>> > >>> > >>> > >>> > >>> > 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 >>> >>> > >>> > >>> > --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 > > Maybe a better solution would be to use the UHD stream commands? Is it possible to issue a sequence of stream commands and have them executed serially by the USRP? Example: * Issue command to send Z samples at clock value M * Issue command to receive X samples at clock value N * Issue command to send Y samples immediately based on the decoded received samples Thanks, Colby
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
