Hi Karsten, Dieter, On Fri, Jan 8, 2010 at 03:11, Karsten Nohl <[email protected]> wrote: > On Jan 6, 2010, at 9:43 PM, Alexander Chemeris wrote: >>> Some people on >>> the list are working on clocking a USRP through a phone so that >>> much less >>> oversampling and much lower data rates become possible. This option >>> might be >>> reserved for the USRP-2, though. >> >> Not sure I understand what do you mean by "clocking a USRP through >> a phone". Could you elaborate a bit, please? > > I was referring to an idea Dieter Spaar had: Use a phone that is > connected to a GSM cell as a source for a very accurate clocking > signal. This trick makes a 'debug' device much simpler.
That's interesting. Have you done any experimentation or at least have any specific design in your mind? Do you plan to get 13MHz a phone or some multiple of it? IIRC USRP1 can't work with clock below about 30MHz, e.g. 26MHz clock can't be used. That's why OpenBTS use 52MHz clock instead of 26MHz. This was thought of as a software problem which can be fixed with later USRP firmware updates, though. But why do you have a problem with oversampling if you can do decimation in USRP FPGA? I should be missing something. PS With our ClockTamer we can drive USRP with any frequency from 3MHz to 65MHz, so we can help if you need some test results with frequencies other then 64MHz. -- Regards, Alexander Chemeris. _______________________________________________ A51 mailing list [email protected] http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51
