Hi Josh, Thanks a lot for your reply. Can I control the TX stream from the GRC generated python code? In other words, can I change the UHD:USRP source/sink parameters to set up the time stamps or controlling the scheduling?
Thanks, Nazmul On Sun, Jul 8, 2012 at 12:30 AM, Josh Blum <j...@ettus.com> wrote: > > > On 07/07/2012 09:30 AM, Nazmul Islam wrote: > > I have three USRP's and I want them to transmit a continuous stream of > > repeated GLFSR source in non-overlapping manner. In other words, each > > transmitter will transmit the source for 1 second and then pause for 5 > > seconds. All transmitters will transmit during the 'odd' seconds so that > > there is a 1 second gap between the sources. This process should continue > > for ever. > > > > Currently, I am controlling the starting and stopping time of the flow > > graphs to achieve my goals. Unfortunately, the code/flowgraph sometimes > > hangs after 15-20 starts. I am using the following code: > > > > ............ > > tb = GLFSR_transmitter() # The Tx flowgraph : GLFSR source (float) --> > > RRC filter --> USRP Sink > > > > var = 1 > > > > while var == 1: # This process should run forever > > > > time.sleep(1-time.time() + int(time.time())) > > > > condition = ((int(time.time())%6) == 0) # The transmitter will > > transmit after every 6 seconds > > > > if (condition): > > > > print time.time() > > > > tb.start() > > > > sleep(1) # The transmitter runs for 1 second > > > > tb.stop() > > > > tb.wait() > > ............................ > > > > You really dont want to stop and start the flow graph. TX streams can be > controlled with stream tags. Links to header docs and example here: > > http://code.ettus.com/redmine/ettus/projects/uhd/wiki/GNU_Radio_UHD#Using-UHD-with-GNU-Radio > > > My USRP's don't seem to like this frequent starting and stopping of flow > > graphs, especially when I am transmitting at 15-20 MS/s rate. I am using > > USRP N210 (SBX daughterboards) and the latest gnuradio images. What other > > things can I do to achieve this timing control? I am looking for options > in > > python level since my C++ OOP background is not strong. Josh talked about > > some python based blocks ( > > ttps://github.com/guruofquality/gnuradio/tree/python_blocks2< > https://github.com/guruofquality/gnuradio/tree/python_blocks2>) > > in (http://old.nabble.com/How-to-implement-a-TDMA-system-td33727749.html > ). > > They seem to be merged to the master ( > > > http://gnuradio.org/redmine/projects/gnuradio/repository/revisions/f8581fb475267e1a97eaab962e423559fb4bfce2 > ) > > but I can't find the blocks. > > > > All that stuff + instructions and coding guide can be found here > https://github.com/guruofquality/grextras/wiki > > -josh > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > -- Muhammad Nazmul Islam Graduate Student Electrical & Computer Engineering Wireless Information & Networking Laboratory Rutgers, USA.
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
