Correction: As Brian stated, I think 0xffffffff is the correct "NOW" timestamp.
On Thu, 2010-08-12 at 09:08 -0600, Eric Schneider wrote: > Sylvain - > > On Thu, 2010-08-12 at 14:27 +0200, Sylvain Munaut wrote: > > > - How can I know the 'current' TX timestamp ? I want to send a ping > > command, but I don't see a way to know what timestamp I should use. > > It is in the header of every Rx packet. If you need to send a command > without knowing the current timestamp, use timestamp = 0, which will > always execute immediately. (There are some caveats which can usually > be ignored) > > > - The timestamp seems imprecise: I often get a timestamp difference > > between two packets of 24191 or 24193 while I should in fact get 24192 > > (I'm at 192 decimation). With such a high decimator, I can fix it up > > myself, but still, that looks weird. > > Which inband code are you using exactly? My inband work (which was in > the ets developer branch) fixed exactly that problem. The root cause > was that time-stamping was done after sample buffering, so the stamps > would vary based on the buffer levels. > > The new code is accurate and reflects the exact value of the 64MHz > counter for the first sample in the packet. There is an additional > offset between rx/tx times at analog due to various signal processing > stages before the time-stamping (which can vary depending on the FPGA > configuration). This value is easily compensated for on the host. > > --Eric S. > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
