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From: | Zohair M. Abu Shaban |
Subject: | RE: [Discuss-gnuradio] Synchronising USRP2's in GRC. |
Date: | Mon, 21 Jun 2010 16:02:55 +0100 |
Doug, Thanks for sharing your solution. I will try it and see what happens. Cheers, Zoh > Date: Mon, 21 Jun 2010 10:05:59 -0400 > Subject: Re: [Discuss-gnuradio] Synchronising USRP2's in GRC. > From: address@hidden > To: address@hidden > CC: address@hidden; address@hidden > > For the old(er) USRP2 driver (i.e. in the current released version of > GNURadio) - the C++ block supports the functionality to synchronize > the clock, and they are available in python as well, but I don't > believe the GRC block exposes this functionality. It would be > relatively trivial to add a drop-down in the block configuration to > select a clock reference. Setting the clock time is a little trickier, > but is do-able in GRC. All the modifications need to be done in the > usrp2_sink_xxxx.xml and usrp2_source_xxxx.xml files ( > > I've been taking a look at doing this with the new UHD driver (i.e. > for the next GNURadio release). The low-level UHD driver supports > synchronizing the LO to the reference clock, and setting the time > according to the PPS (or just according to when you tell it to via the > set_time_now()), however the gr-uhd block does not yet. Adding this > functionality is relatively trivial for the C++ code, but I've run > into a problem with SWIG-izing the calls (for use with GRC) due to the > UHD's use of boost::uint32_t in the time_spec_t structure. As I'm not > a SWIG expert, any advice on how to deal with this would be > appreciated. I do expect to be able to share the patch when I get it > working. > > The particular problem I run into is that time_spec_t is defined to > want a boost::uint32_t in the constructor (for the number of seconds), > along with a double (for fractional seconds) - but SWIG apparently > doesn't recognize boost::uint32_t is a typedef for an integer type, so > while I don't get compile-time errors, by the time I fire up python to > test out the function call (set_type_next_pps(const uhd::time_spec_t > &time_spec) in this case) - and try to construct a time_spec_t object > to pass, python throws an error as it doesn't believe I'm passing the > correct type. > > Doug > > On Mon, Jun 21, 2010 at 7:02 AM, Zohair <address@hidden> wrote: > > > > Hi everyone, > > > > I need to use several USRP2's in the same GRC programme (MIMO). Is there a > > way to sychronise them to the same clock in GRC itself? > > > > Best, > > > > Zoh > > -- > > -- > Doug Geiger > address@hidden Get a free e-mail account with Hotmail. Sign-up now. |
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