[Discuss-gnuradio] message_source repeatly transmit msg 10times

[Yan Nie]

Dear all,

I'm using message_source generate data source then modulated and transmitting 
through USRP1 board with LFTX plugged-in. After building the flow graph, I used 
the msgq_insert to insert 1950 bytes data into the flow graph to be 
transmitted, then insert another group of data which is 97500 bytes into the 
the flow graph. The result turns out these two group of data are repeatly sent 
10 times. What could be the problem here?

This problem really troubles me for a while and it seems to be the biggest 
problem that I really need to solve for my project, and I dug into the source 
code related to message_source and gr_message, but couldn't get any clue why 
this happens here. Really need your help!

Really appreciate any of you help!

Thanks,
Yan

the code related:
#message_source in tb block
indata = gr.message_source(gr.sizeof_char, 1950)
msgq = indata.msgq()
constellation = [-1,1]
mapper = chunks_to_symbols_bf(constellation)
#setup USRP and signal amplitude setting......
usink  = ...
connect(indata,mapper,usink)

#flowgraph running in main
try:
   tb.start()
   while 1:  
          i = 0
          tb.set_amp(5000)
          msg_13bit = gr.messge_from_string(payload_13bit) #payload_13bit is 
1950 bytes
          tb.msgq.insert_tail(msg_13bit)
          tb.set_amp(0)
          while (i<50)
              msg_stop = gr.message_from_string(payload_stop) #payload_stop is 
1950 bytes
              tb.msgq.inset_tail(msg_stop)
              i +=1
    tb.wait()