[Discuss-gnuradio] Tx/Rx using one USRP board

[pratik hetamsaria]

hi,

I am posting this again as i havent got any concrete replies.I have been stuck making the usrp work as a relay for a very long time. I am giving the code which i am using for making it work as a relay. Can somebody please point out where is the mistake. I am trying to receive a signal sent by usrp_siggen.py at 910MHz and retransmit it at 950MHz. However, when i view the signal at 950MHz using usrp_oscope.py then i am able to see only noise. There is no sine wave present at that frequency. I am not able to understand what is the usrp transmitting at 950 MHz then. What i know is that the usrp does receive the sine wave at 910MHz.

PLease point out where is the mistake in my code.

Thanks
Pratik Hetamsaria

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class my_graph(gr.flow_graph):

    def __init__(self):
        gr.flow_graph.__init_
 _(self)
    
    parser = OptionParser(option_class=eng_option)
        parser.add_option("-R", "--rx-subdev-spec",  type="subdev", default=None)
        parser.add_option("-d", "--decim", type="int", default=256)                   
        parser.add_option("-f",  "--freq", type="eng_float", default=910e6)
        parser.add_option("-g", "--gain", type="eng_float", default=45)
        parser.add_option("-T", "--tx-subdev-spec", type="subdev", default=None) 
        parser.add_option("-a", "--tx-amplitude", type="eng_float", default=32000)
        parser.add_option("-q", "--tx-freq", type="eng_float",
 default=950e6) 
        parser.add_option("-i", "--interp", type="intx", default=512)
        (options, args) =  parser.parse_args()

    rx_src = usrp.source_c (0, options.decim)
    rx_subdev_spec = (0,0) 
    rx_src.set_mux(usrp.determine_rx_mux_value(rx_src, rx_subdev_spec))
    subdev = usrp.selected_subdev(rx_src,  rx_subdev_spec)
    r = rx_src.tune(0, subdev, options.freq)
    
    self._tx_amplitude = options.tx_amplitude
    self.amp = gr.multiply_const_cc(0)     self.amp.set_k(self._tx_amplitude)

    dst = usrp.sink_c(0, options.interp)
    if options.tx_subdev_spec is None:
            tx_subdev_spec =
 usrp.pick_tx_subdevice(dst)
     dst.set_mux(usrp.determine_tx_mux_value (dst, tx_subdev_spec))
    subdev = usrp.selected_subdev(dst, tx_subdev_spec)
    r = dst.tune(subdev._which, subdev, options.tx_freq )
    
    filename = "/home/polytech/Desktop/usrp_data_receive.dat" 
    destination = gr.file_sink(gr.sizeof_gr_complex, filename)

    self.connect(rx_src,  destination)
    self.connect(rx_src, self.amp, dst)

if __name__ == '__main__':
    try:
        my_graph().run()
    except KeyboardInterrupt:
        pass

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