Understood. Thanks. Let me try this out. Regards Snehasish
Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10 From: Marcus Müller<mailto:marcus.muel...@ettus.com> Sent: 06 March 2021 23:41 To: Snehasish Kar<mailto:snehasish....@live.com>; usrp-users@lists.ettus.com<mailto:usrp-users@lists.ettus.com> Subject: Re: [USRP-users] Phase synchronization after hopping See the tuning notes in the UHD manual. I'm assuming you're not explicitly setting POLICY_MANUAL without reason! Best regards, Marcus On 06.03.21 18:43, Snehasish Kar wrote: > > Thanks Marcus for the prompt response. Can you please help me with an example > showing > DSP tuning. I have gone through Piotr’s implementation, but was not able to > understand > how he was maintaining the time synchronization based on GNURadio work > function. > > > > Regards > > > > Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10 > > > > *From: *Marcus Müller via USRP-users <mailto:usrp-users@lists.ettus.com> > *Sent: *06 March 2021 23:00 > *To: *usrp-users@lists.ettus.com <mailto:usrp-users@lists.ettus.com> > *Subject: *Re: [USRP-users] Phase synchronization after hopping > > > > Hi Snehasish, > > you're not actually using timed commands, so there's no exact timing > involved. Your usleep > doesn't make much sense either, you shouldn't let your PC sleep while the > analog chain > tune, but instead already issue the next timed command. In this situation, I > also would > *not* tune the RF frontend *at all*, but only use DSP tuning (maybe you're > doing that, no > idea where your "rf_freq" and "dsp_freq" come from). > > Piotr Krysik solved your exact problem (X310, following GSM hopping) before. > I remember > the talk he held at an OsmoDevCon some years ago, maybe look for that. > > Best regards, > > Marcus > > On 06.03.21 17:31, Snehasish Kar via USRP-users wrote: > > > > Hello everyone > > > > > > > > I am trying to achieve frequency hopping in GSM using twinrx with usrp > > x310. Here I am > > using timed command for tuning a single port across a given frequency list. > > During > > hopping it stays in each frequency for 4msecs and till the time frequency > > hopping > > continues, I am able to identify FCCH using phase difference. But as soon > > as the hopping > > is over and it tunes back to the actual frequency containing the broadcast > > channel, I am > > not getting phase difference greater than 0 and thus not able to demodulate > > the GSM > > burst. Can anyone please help where I am going wrong below is the snippet > > of the code, > > responsible for hopping. > > > > > > > > Function handling hopping: > > > > > > > > uhd::tune_request_t tune_request(rf_freq); > > > > tune_request.rf_freq_policy = > > uhd::tune_request_t::POLICY_MANUAL; > > > > tune_request.dsp_freq_policy = > > uhd::tune_request_t::POLICY_MANUAL; > > > > tune_request.rf_freq = rf_freq; > > > > tune_request.dsp_freq = dsp_freq; > > > > uhd_src->set_rx_freq(tune_request, chan_num); > > > > { > > > > If(verbose_lvl==3){ > > > > char msg[100]={0x00}; > > > > sprintf(msg,"info: DSP freq: > > changed to channel > > %d: %fMHz offset %fMHz", chan_num, uhd_src->get_rx_freq(chan_num)/1e6, > > dsp_freq); > > > > vipl_printf(msg,error_lvl, > > __FILE__, __LINE__); > > > > } > > > > } > > > > //uhd_src->clear_command_time(); > > > > usleep(110000); // allow LOs to lock > > > > > > > > > > > > > > > > Module for setting back to original frequency with broadcast: > > > > > > > > uhd_src->clear_command_time(); > > > > uhd::tune_request_t tune_request(rf_freq, 0x00); > > //considering LO-Offset > > to be zero > > > > tune_request.rf_freq_policy = > > uhd::tune_request_t::POLICY_AUTO; > > > > tune_request.dsp_freq_policy = > > uhd::tune_request_t::POLICY_AUTO; > > > > tune_request.rf_freq = rf_freq; > > > > //tune_request.dsp_freq = -dsp_freq; > > > > uhd_src->set_rx_freq(tune_request, channel); > > > > { > > > > char msg[100]={0x00}; > > > > sprintf(msg,"info: freq: set to channel %d: > > %fMHz requested > > freq %fMHz", channel, uhd_src->get_rx_freq(channel)/1e6, rf_freq/1e6); > > > > vipl_printf(msg,error_lvl, __FILE__, __LINE__); > > > > } > > > > usleep(110000); > > > > > > > > My UHD version is 3.14.0.0 > > > > USRP: X310 > > > > Daughter board: 2 sets of Twinrx > > > > OS: Debian 10 > > > > Interface: 10gig sfp+ ethernet > > > > > > > > Thanks!! > > > > > > > > > > > > Regards > > > > Snehasish Kar > > > > > > > > Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986 > <https://go.microsoft.com/fwlink/?LinkId=550986>> for Windows 10 > > > > > > > > > > _______________________________________________ > > USRP-users mailing list > > USRP-users@lists.ettus.com > > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > <http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com> > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > <http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com> > > >
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