If I understand correctly, the sample count is: const uint64_t count = gr_tags::get_nitems(rx_time_tag);
This determines the index of the sample coming into work, which has a new time because of overflow. juha On Wed, Oct 26, 2011 at 17:16, Josh Blum <[email protected]> wrote: > > > On 10/26/2011 03:41 AM, Juha Vierinen wrote: >> Hi, >> >> I have been able to use the stream tagging to determine the accurate >> timing for the first sample of the stream. However, I run into >> problems after an overflow. It does seem to be feasible to recover >> timing by looking for new tags (the uhd_usrp block applies a new tag >> after an overflow is detected). However, this pmt is too alien to me >> still and I'm not exactly sure how to query for the sample index >> corresponding to the new tag. Are there any examples anywhere? I know >> how to query for the tags between some interval of samples, but I >> cannot get the exact sample corresponding to the first sample of the >> packet arriving after overflow. >> > > The tag's offset field provides the absolute sample count of the tag. > Knowing the sample rate, the delta between the tag's offset and your > sample; you can determine the absolute time for each proceeding sample. > > Your code was probably making an assumption that the time was at offset > zero; but really the absolute time can be referenced at any offset. > > http://gnuradio.org/cgit/gnuradio.git/tree/gnuradio-core/src/lib/runtime/gr_tags.h > > -josh > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
