Multiple USRP1 and UHD

Hello list,

I have two USRP1s and four DBSRX2 daughterboards. I would like to
synchronise the USRPs, to build a coherent, sample aligned, four channel
receiver (inputs from four separate antennas). I had hoped I could do
this by modifying and connecting the boards as described here:

http://gnuradio.org/redmine/wiki/1/USRPClockingNotes
http://gnuradio.org/redmine/wiki/1/MultiUsrp

And then modifying the usrp_multi code to work with UHD. If this
approach works, it looks like I have to replace the lines (amongst
others):

u1 = usrp.source_s (1, decim, nchan, gru.hexint(mux),
mode,fpga_filename=“multi_2rxhb_2tx.rbf” )
u0 = usrp.source_s (0, decim, nchan, gru.hexint(mux),
mode,fpga_filename=“multi_2rxhb_2tx.rbf” )

But, how do I set the mux and mode values if I replace these with
instances of uhd.single_usrp_source? And is the multi_2rxhb_2tx.rbf
image likely to work still with UHD? I’m pretty new to this so any
pointers, or suggestions for a better approach, appreciated…

I’m also having problems with the UHD multi_usrp_source, trying to use
this in GRC for some initial experiments with the boards unsynced. With
Num Mboards = 2, device addresses of either “serial=XXXXXXXX,
serial=YYYYYYYY” or “name=usrp_master, name=usrp_slave” (either way
round) and the same subdev spec “A:0 B:0” for both, I can find the first
board but not the second. Maybe I’ve just got the syntax wrong or is
there another problem?

File “/home/ac2/grc/top_block.py”, line 70, in
tb = top_block()
File “/home/ac2/grc/top_block.py”, line 40, in init
self.uhd_multi_usrp_source_0.set_subdev_spec(“A:0 B:0”, 1)
File
“/usr/local/lib/python2.6/dist-packages/gnuradio/uhd/uhd_swig.py”, line
887, in set_subdev_spec
return _uhd_swig.uhd_multi_usrp_source_sptr_set_subdev_spec(*args,
**kwargs)
RuntimeError: vector::_M_range_check

With Num Mboards = 1, I get past this point but not much further:

thread[thread-per-block[0]: <gr_block uhd multi_usrp source (3)>]:
cannot get this property
in void usrp1_impl::mboard_get(const wax::obj&, wax::obj&)
at /home/ac2/gnuradio-uhd/uhd/host/lib/usrp/usrp1/mboard_impl.cpp:329

What’s going wrong here? Two separate single sources works fine. I’m
using a fairly recent build, source downloaded from git on 3rd Jan, and
Ubuntu 9.04 for what that’s worth.

Thanks,
Andy

Roke Manor Research Ltd, Romsey,
Hampshire, SO51 0ZN, United Kingdom

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But, how do I set the mux and mode values if I replace these with

The mux value calculation is not exposed. Rather, you specify channel
mappings:
http://www.ettus.com/uhd_docs/manual/html/usrp1.html#specifying-the-subdevice-to-use

instances of uhd.single_usrp_source? And is the multi_2rxhb_2tx.rbf
image likely to work still with UHD? I’m pretty new to this so any
pointers, or suggestions for a better approach, appreciated…

The following images ship with uhd for USRP1:
http://www.ettus.com/uhd_docs/manual/html/usrp1.html#specify-a-non-standard-image

I am unaware of a “multi_2rxhb_2tx.rbf”

I’m also having problems with the UHD multi_usrp_source, trying to use
this in GRC for some initial experiments with the boards unsynced. With
Num Mboards = 2, device addresses of either “serial=XXXXXXXX,
serial=YYYYYYYY” or “name=usrp_master, name=usrp_slave” (either way
round) and the same subdev spec “A:0 B:0” for both, I can find the first
board but not the second. Maybe I’ve just got the syntax wrong or is
there another problem?

Ganging together multiple USRP1s into a “multi usrp” is not supported.
This is supported on USRP2/N-Series because of the time alignment
capabilities. But it wouldnt make sense to implement for the USRP1
because its just as useful as multiple “single usrps”.

-josh

Hi,

I am thinking to integerate my SystemC code as a SP block with
GNURadio…

Is there anyone who have experience/example about this?

SystemC is a C++ library.

rgs

Tao

Hi,

I am thinking to integerate my SystemC code as a SP block with
GNURadio…

Is there anyone who have experience about this?

SystemC is a spereate C++ library.

rgs

Tao

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