Adding dual usrp sink block to benchmark_tx.py

GNU Radio
1

Hello everyone,

I’ve added a dual usrp sink block and duplicated the tx flow graphs in
benchmark_tx.py example. However, I am unable to transmit packets when I
set the following in the flow graph:

self.packet_transmitter =
blks2.mod_pkts(modulator,
access_code=None,
msgq_limit=4,
pad_for_usrp=True)

self.packet_transmitter_2 =
blks2.mod_pkts(modulator_2,
access_code=None,
msgq_limit=4,
pad_for_usrp=True)

self.connect(self.packet_transmitter, self.amp, (self, 0))
self.connect(self.packet_transmitter_2, self.amp_2, (self, 1))

I have tried the following 2 codes and were able to transmit packets
from the first flow graph, and then the packets from the second flow
graph:

self.connect(self.packet_transmitter, self.amp, (self, 0))

self.connect(self.null_source, self.amp_2, (self, 1))

self.connect(self.null_source, self.amp, (self, 0))

self.connect(self.packet_transmitter_2, self.amp_2, (self, 1))

Any idea why I am unable to simultaneously transmit packets from both
flow graphs? Thanks in advance!

2

On Sat, Feb 26, 2011 at 5:17 AM, Jay G. [email protected] wrote:

                       pad_for_usrp=True)

graphs? Thanks in advance!

Right now, no, sorry, no ideas. It seems like it should work.

I will suggest two things, though. First, remove the message sources
from
the graph. Replace your packet_transmitter_X and replace them with two
gr.sig_source_c() with different frequencies and make sure that they
transmit as expected from each output of the USRP.

Next, keep your packet transmitters, but replace the USRP dual sink with
file sinks and make sure they are getting the proper signals from the
source.

Between these two experiments, maybe you’ll get enough information to
fix
your problem. Or let us know more about what’s happening to be more help
to
you.

Tom