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 Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
