Hello Marcus, I'm aware of that, what I want to achieve at the moment is simply to have a predictable phase delay between the tx and rx channels. This is prerequisite to measure the round-trip time and account for it.
Cheers, Daniele On 22/07/2014 22:14, Marcus Müller wrote: > Hi Daniele, > > your problem is actually harder: The latency of digital signal > processing depends on your desired decimation, and analog signal latency > depends on a ton of factors like target RF frequency, adjustable filters > (if your daughterboard has something like this), antenna and cabling > delay, and so on. > The only real way to know is to *measure* the roundtrip for each > configuration, and that's exactly what echotimer is for. > > With best regards, > Marcus > > On 22.07.2014 19:25, Daniele Nicolodi wrote: >> Hello Stephan, >> >> thank for your reply. What I would like to do is more simple than that: >> I need to synchronize tx and rx of the same USRP, not of two different >> devices. But I need continuous streaming and not burst. >> >> Any help in this direction is much appreciated. >> >> Thanks. Best, >> Daniele >> >> >> On 22/07/2014 19:14, Stefan Wunsch wrote: >>> Hey Daniele, >>> >>> I have done the radar toolbox and implemented a synced USRP interface >>> (USRP Echotimer). >>> >>> You are right, the USRP Echotimer does align the timestamps of the TX/RX >>> commands on both USRPs. But if you connect them by MIMO, the time and >>> clock are pretty good in sync. Therefore I think the Echotimer can >>> provide a sync with an accuracy of at least +- 1 sample. Check out [0] >>> for a video of the sync. There is also a sync setup for testing >>> (gr-radar/examples/usrp). Unfortunately the documentation is not >>> finished yet. >>> >>> But care: The Echotimer bursts only a packet in sync, it does not stream >>> the whole time! The packet is defined by a tagged stream. >>> >>> Greetings, >>> Stefan >>> >>> [0] >>> https://grradar.wordpress.com/2014/06/17/synchronisation-echotimer-usrp-interface/ >>> >>> Am 22.07.2014 18:40, schrieb Daniele Nicolodi: >>>> On 22/07/2014 18:18, Martin Braun wrote: >>>>> On top of what Marcus' has said, >>>>> >>>>> the gr-radar toolbox might be helpful. It has a block that takes a >>>>> tagged stream, and outputs a signal it acquired synchronously to the >>>>> transmitted one. >>>> Thanks Martin. This seems to imply that there is no way to actually >>>> synchronize the hardware, and that the synchronization can only be done >>>> in software aligning the timestamps of the two streams. Is that the case? >>>> >>>> Thanks. Cheers, >>>> Daniele >>>> >>>> >>>> _______________________________________________ >>>> 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 > > > _______________________________________________ > 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
