On Tue, Feb 03, 2009 at 02:33:15PM -0600, Douglas Geiger wrote: > Is there any code similar to usrp_multi.py to use multiple USRP2's > already (or is it unnecessary)? As I understand it, with the USRP2, you > either use the MIMO cable, or an external reference to synchronize the > clocks - then on the host side you would still need to do the > align_on_samplenumbers/deinterleaving, etc. business that usrp_multi.py > took care of for the USRP1. > > If nobody has code available to do this, should I expect any major > hurdles in trying to convert the usrp_multi.py for use with the USRP2 > (besides converting the source create calls, removing the subdev calls, > etc)? > If I'm using the MIMO cable, do I need to make any additional settings > (e.g. sync_to_pps(True) or similar) to synchronize the master to slave? > http://gnuradio.org/trac/wiki/USRP2GenFAQ says the VCXO locks on to the > external reference, if one exists - which implies this is also the case > for the MIMO cable, just wanted to verify that was true. > Looking at test_mimo_tx.cc in the u2-mimo-wip branch I see it is > possible to setup one usrp2 interface, and send samples to different > channels - is that accessible from python now - or is it still code > that's in development? If that's the case, is it possible at all to get > synchronized samples out of two usrp2's with a MIMO cable right now with > python, or should I be writing something in C++ to do that for me? > Perhaps > Thanks, > Doug
Doug, There's currently no production code that supports using the USRP2 and the MIMO cable. We have test code that confirms that the h/w works as we expect, but we're not going to sort this out until after "the great reworking" of the host, firmware and on-the-wire spec as part of our move toward VITA-49 (VITA Radio Transport), an emerging standard for digital IF. In the meanwhile, you can make this work by providing your own star-distributed 10 MHz reference and PPS. All USRP2's will be coherent and will share the same timestamps. You will have to invoke config_mimo(MC_WE_LOCK_TO_SMA) and sync_to_pps() on each USRP2. Eric _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
