New code to support multiple linked phase-coherent usrps in


#1

New Multi usrp code in cvs/svn now.

With this code you can connect two or more usrps (with a locked clock)
and get synchronised samples.
The samples should be phase-coherent with a 1 sample accuracy.

You must connect a (flat)cable between a dboard on the master in RXA and
a dboard on the slave in RXA.
(You only need to connect io15)
You then put one usrp in master mode, put the other in slave mode.
Then you call sync() at least once AFTER the flow_graph started
running.

The easiest thing to see how this works is just looking at the example
code in
gnuradio-examples/python/multi_usrp/README
gnuradio-examples/python/multi_usrp/multi_usrp_oscope.py
gnuradio-examples/python/multi_usrp/multi_usrp_rx_cfile.py

CONNECTING THE CLOCKS
Connect the 64MHz clocks between the boards with a short sma coax cable.
(See the wiki on how to enable clock-out and clock-in
http://comsec.com/wiki?USRPClockingNotes )

You need one board with a clock out and one board with a clock in.

For how to connect the sync (flat)cable see
gnuradio-examples/python/multi_usrp/README
and/or
gr-usrp/README_MULTI_USRP.txt

This work was funded by Toby Oliver at Sensus Analytics / Path
Intelligence.
Many Thanks for making this possible.

It was written by Martin Dudok van Heel at Olifantasia.

You need to have updated versions of usrp, gr-usrp, gnuradio-core and
gnuradio-examples.
(cvs/svn checkouts from 11 may 2006 or later)

The code works with the special multi_usrp firmware multi_2rxhb_2tx.rbf
which is installed by usrp.
(The examples automatically use this firmware)

Greetings,
Martin Dudok van Heel