> I have not yet used stream tags, and have a number of > questions: > > 1. Is it possible to get timetags for every sample? My > readings on time tags seemed to imply that only one > is created at the beginning of a stream. >
Your block will need to grab a hold of the last time tag that was produced. If you know the sample count of this tag, and the sample count of the sample you are interested in, its a simple interpolation. > 2. What is the accuracy/precision of the time tags? Jitter > is going to be the make-or-break factor on this project. > The fractional seconds are stored as double precision floating point. This gives the fractional seconds enough precision to unambiguously specify a clock-tick/sample-count up to rates of several petahertz. :-) > 3. It looks like the Start-Of-Burst (SOB) tag is the only > way to control the time of transmission. Is there any > limitation on the length of a burst? In my case, I would > want to start the transmitter in response to receiving > the uplink, and not stop it until the uplink ceases, > about 4 minutes later. > The tx_time tag is the way to control the time of transmission. Bursts can be any length. Its important to end a burst or an underflow is produced if you stop producing TX samples. > 4. Is there any good tutorial or example information on > the use of stream tags? (I'm using GR 3.6.1) Yes: http://gnuradio.org/cgit/gnuradio.git/tree/gr-uhd/examples/c++/tags_demo.cc > > 5. Does all this sound like I'm headed in the right direction, > or is there something fundamental that I'm missing? > I think you have got it! http://code.ettus.com/redmine/ettus/projects/uhd/wiki/GNU_Radio_UHD#Using-UHD-with-GNU-Radio -josh _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
