RE: [Discuss-gnuradio] Re: FRS with the FLEX400

[Kevin Rudd \(Contractor\)]

Yes,
  I started there and it did not work well (the gain defaults too low).
Looking in the code of that program, I see it is supposed to have controls
for setting the gain, volume frequency, via the GUI, but I do not see these
when it runs.

I can now receive/send fm signals from/to an FRS radio with the FLEX400
using my own simple code.  I am starting to pick up on the coding techniques
and the layout of GNURadio.  Next step is to do both at the same time...

Thanks for the help.
Kevin



-----Original Message-----
From: Matt Ettus [mailto:address@hidden 
Sent: Tuesday, April 24, 2007 3:26 PM
To: Kevin Rudd (Contractor)
Cc: address@hidden
Subject: Re: [Discuss-gnuradio] Re: FRS with the FLEX400



Have you tried using the existing usrp_nbfm_ptt.py?  It is intended for 
exactly this application.

Matt

Kevin Rudd (Contractor) wrote:
> Hello again,
>   Thanks for those that emailed me directly with my last request.  I have
> been able to get my transmit code to tune now, but it is still not
working.
>
> All I am trying to do is fm modulate a sine wave and transmit it at a
> certain frequency.  I have hooked up a vector signal analyzer and I see no
> output from the USRP.  Could I have a dysfunctional daughter card?
>
> My newer code is below.  Any help would be appreciated.
>
> Kevin Rudd
> Naval Research Laboratory
>
> myfm.py
> ------------------------------------------------------
> #!/usr/bin/env python
>
> from gnuradio import gr, eng_notation
> from gnuradio import usrp
> from gnuradio import audio
> from gnuradio import blks
> from gnuradio.eng_option import eng_option
> import usrp_dbid
> import sys
>
>
> class my_graph(gr.flow_graph):
>
>       def __init__(self):
>               gr.flow_graph.__init__ (self)
>               
>               self.u = usrp.sink_c ()       # the USRP sink (consumes
> samples)
>                 
>             # Setup Constants
>               self.dac_rate = self.u.dac_rate()                    # 128
> MS/s
>               self.usrp_interp = 400
>               self.u.set_interp_rate(self.usrp_interp)
>               self.usrp_rate = self.dac_rate / self.usrp_interp    # 320
> kS/s
>               self.sw_interp = 40
>               self.audio_rate = self.usrp_rate / self.sw_interp    # 8
> kS/s
>
>               # Determine the daughterboard subdevice we're using
>               tx_subdev_spec = usrp.pick_tx_subdevice(self.u)
>               m = usrp.determine_tx_mux_value(self.u, tx_subdev_spec)
>               self.u.set_mux(m)
>               self.subdev = usrp.selected_subdev(self.u, tx_subdev_spec)
>               print "Using TX d'board %s" % (self.subdev.side_and_name(),)
>
>             # make blocks and connect them
>             src0 = gr.sig_source_f (self.audio_rate, gr.GR_SIN_WAVE, 350,
> 1)
>             fmtx = blks.nbfm_tx (self, self.audio_rate, self.usrp_rate,
>                              max_dev=2.5e3, tau=75e-6)
>               gain = gr.multiply_const_cc (4000.0 );
>               
>             self.connect (src0,fmtx,gain,self.u)
>
>             # set gain, tune, and turn on transmitter 
>             self.subdev.set_gain(self.subdev.gain_range()[1]) #max Tx gain
>             self.u.tune(self.subdev._which, self.subdev, 462562500)
>             #self.set_freq(462562500)
>             self.subdev.set_enable(True)        # enable transmitter
>               
> if __name__ == '__main__':
>       try:
>               my_graph().run()
>       except KeyboardInterrupt:
>               pass
>
>
>
>
>
>
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