Questions about chaning the fpga codes to synchronize the TX signals between USRPs

Hi all,

The problem is like this,

The two USRP1s will send the same number of bits, and then I want to
synchronize them in an easy way. Both of them trigger the TX signals at
the same time. The requirement of synchronization is not strict and
there can be a few disorder samples between them. And I will do these
things:

(1)According the USRP clocking
notes(http://gnuradio.org/redmine/wiki/1/USRPClockingNotes), to
synchronize the 2 USRP1s.

(2)Considering the notes of
MultiUSRP(http://gnuradio.org/redmine/wiki/gnuradio/MultiUsrp), I will
select two unused IO pins from FPGA, and connect the two IO pins between
Master and Slave USRP1s. One pin is used for the state of the TX buffer
in Slave USRP1 and the other is used for the state of the TX buffer in
Master USRP1.

(3)In Verilog codes of USRP1,

Wire tx_empty_new = tx_empty(Master) || tx_empty(Slave);

Changing the tx_empty in module of mater_control into tx_empty_new, and
then the faster one will wait for thesubsequent one to trigger the TX
signal at the same time.

So the method is OK or it is not so easy? Would you give me some
suggestion or a better way to do this? Thank you very much.

With thanks & regards,
Fenix
HKUST
Tel:+852-67635787