usrp_multi and the USRP2Is 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? PerhapsThanks, Doug Doug Geiger Research Assistant Communications and Signal Processing Lab Oklahoma State University http://cspl.okstate.edu Re: usrp_multi and the USRP2Doug, 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 (Eric Blossom) Re: usrp_multi and the USRP2Understood.Looking around at code that uses config_mimo (which looks like it's only available to C++ apps right now) - I see rx_samples.cc uses it, but it looks like that's fallen out of use, and is a bit crufty now. Any reason I couldn't modify rx_streaming_samples.cc to call config_mimo? Thanks, Doug -- Doug Geiger Research Assistant Communications and Signal Processing Lab Oklahoma State University 注：usrp_multi and the USRP2 （英文原文出处，以上翻译整理仅供参考 Email: support@microembedded.com !） |
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