Vadim Uvin wrote: > Thanks for the suggestion, Sylvian. But it is not the case, since the > GSM does not use inband signalling.
? I'm taking about inband signalling for the USRP where the USRP marks each sample received with a timestamp. > Buying the second DBSRX is not very > convenient since I in the future I want to try to implement channel > hopping. That is why I'm wondering is it feasible at all to change USRP > frequency fast enough to keep up with the GSM. By the way, the delay > should be comparable to about 1 ms. > > Also, the downlink and uplink channel separation is at least 45 MHz, so > I cannot cover it with USRP's 8 MHz. > > 2009/12/8 Sylvain Munaut <[email protected] <mailto:[email protected]>> > > Vadim Uvin wrote: > > I have USRP+DBSRX. I'm trying to listen to uplink channel (MS->BTS) of > > GSM. To do that, I first need to be synced with the BS (i.e. listen to > > synchronization channel of BTS). Then I have to change the center > > frequency to uplink channel, but I need to know how long it takes > before > > USRP gets stable or I can lost the synchronization. Unfortunately, I > > can't find what the tune delay of DBSRX is. Maybe someone knows? > > You should use inband signalling, this way you have a 'sample' counter > and you know precisely 'where' you are in time. > > Or you use two dbsrx, following both up & downlink .... > > Sylvain > > _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
