On Wed, Feb 23, 2011 at 9:25 AM, Yan Nie <yn...@uwo.ca> wrote: > Dear all, > I'm really sorry about the last uncompleted email. I elaborated the method > lock() and unlock() to completely pause the flow graph without transmitting > any signal, even if the carrier wave, but the continuous carrier wave still > shows on the oscilloscope. I'm trying to transmit 13-bit Barker code carried > by a 4MHz sinusoid wave. After this 13-bit code transmission, the whole > system need to be suspended for 5 milliseconds without any signal > transmitted even the carrier signal. I tried the lock/unlock method, so that > the Barker code won't feed in the flow graph, but the carrier signal, a 4MHz > sinusoid wave is still transmitted through the transmitter. Could you please > help me see what's the problem of the flow graph that cannot allow the > lock/unlock completely disable the signal transmission for 5 ms then restart > the transmission again. At the transmission pause interval, how to > completely shut down the transmission for 5 ms then restart the signal > transmission. > > The code related to the scheduling part is: > > top_block = tx_bpsk_block(options.tx_subdev_spec,options.freq, > options.verbose, options.chip_rate,options.amplitude) > > try: > top_block.start() > start_flag = 1 > payload_13barker = '\x01\x01\x01\x01\x01\x00\x00\x01\x01\x00\x01\x00\x01' > while (start_flag == 1) > msg_13bit = gr.message_from_string(payload_13barker) > top_block.msgq.insert_tail(msg_13bit) > eof_msg = gr.message(1) > top_block.msgq.insert_tail(eof_msg) > top_block.lock() > time.sleep(0.005) > top_block.unlock() > top_block.wait() > except KeyboardInterrupt: > pass > > if __name ___ == "__main__": > main() > > The top block is built as: > > class tx_bpsk_block(gr.top_block): > def __init__ (self, subdev_spec,freq,verbose,chip_rate,amplitude): > gr.top_block.__init__(self,"tx_mpsk") > self._freq = freq > self._verbose = verbose > self._amplitude = amplitude > self._u = > usrp_sink_s(0,subdev_spec,chip_rate,self._freq,self._verbose) > self.in_data = gr.message_source(gr.sizeof_char,14) > self.msgqq = self.in_data.msgq() > self._constellation = [-1,1] > self._mapper = gr.chunks_to_symbols_bf(self._constellation) > self._gain = gr.multiply_const_ff(self._amplitude) > self.f2s = gr.float_to_short() > self.connect(self.in_data,self._mapper,self._gain,self.f2s,self._u) > > Could you please help me to see how to completely pause the signal > transmission at the transmitter side, disabling or shutting down the signal > transmission including transmitting carrier wave? I really appreciate all of > your help on solving this problem. Really appreciate! > Wish you a great day!
Yan, Please confirm that you just see the carrier, not your modulated signal when using the lock()/unlock() Also, please tell us: What version of GNUradio are you using? What hardware are you using? USRP? which daughterboard? Are you using UHD? Jason _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
