Hello Felipe, The oscillator will *start* tuning at the time stamp you specify. You will have to characterize the settling time for your frequency hops and schedule the tunes in advance of when you need to be at the new frequency. Depending on what frequencies you are moving between and which daughterboard you are using the settling time changes. It is important to note that timed commands are executed in the order the are issued, not in chronological order, so you must issue them in chronological order for to get the expected behavior.
Regards, Derek On Tue, Jun 19, 2018 at 3:45 PM, Felipe Augusto Pereira de Figueiredo < zz4...@gmail.com> wrote: > Dear Derek, thanks for your prompt reply! > > I'm using an x310. > > Just to clarify, I want to make sure that the frequency I'm setting is > only valid and guaranteed for that specific starting point (the > timestamp into the future). Right now, when I send just the time > command and change the frequency for the next packet I see with the > spectrum analyser that the packets do not have the right frequency, > instead, they are spread over the spectrum as the oscillator might be > still under configuration, calibration, etc. > > Therefore, I hope that with the timed commands I will be able to have > a better control over freq/time resources. > > Thanks and Kind Regards, > > Felipe > > On Tue, Jun 19, 2018 at 4:37 PM, Derek Kozel <derek.ko...@ettus.com> > wrote: > > Hello Felipe, > > > > Yes it is possible. What USRP are you using? Some, such as the B200 and > E310 > > cannot set the frequency using timed commands as the tuning is done by > the > > RFIC rather than the FPGA. There is a small example of tuning in the > manual. > > http://files.ettus.com/manual/page_sync.html#sync_phase_lo > > > > And a longer program using timed commands in the examples. > > https://github.com/EttusResearch/uhd/blob/maint/ > host/examples/test_timed_commands.cpp#L74 > > > > The TwinRX fast frequency hopping example does not show the use of timed > > commands for changing the local oscillator frequency, but does show very > > efficient burst reception. > > https://github.com/EttusResearch/uhd/blob/maint/ > host/examples/twinrx_freq_hopping.cpp > > > > Regards, > > Derek > > > > > > On Tue, Jun 19, 2018 at 3:15 PM, Felipe Augusto Pereira de Figueiredo via > > USRP-users <usrp-users@lists.ettus.com> wrote: > >> > >> Dear All, > >> > >> I've seen that with the gnuradio API it is possible to set a frequency > >> and time in the future for a bursty transmission. With that feature it > >> is possible to implement frequency hopping without any big trouble. > >> > >> I'd like to know if the same is possible with the UHD API, and if so, > >> how can I do that? One example would be great. > >> > >> Thanks and Kind Regards, > >> > >> Felipe Augusto > >> > >> _______________________________________________ > >> USRP-users mailing list > >> USRP-users@lists.ettus.com > >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > >
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