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#1

Hello,

I am trying to implement a transceiver (Full Duplex) with a Basix TX
board and TVRX board.

I generate a sine wave(3500 Hz) and transmit using Basix Tx at 100MHz.

I also want to tune the TVRX board to 100MHz and receive the same signal
and plot it on the scope in the GUI.

I tried the following code. But I did not get any received signal in the
scope.

Please let me know what could be the problem and the corrections needed
to make it work.

Thanks a lot.
Sivaram

#!/usr/bin/env python
from gnuradio import gr, usrp
from gnuradio.wxgui import stdgui2, scopesink2
import wx

class wfm_scope(stdgui2.std_top_block):
def init(self, frame, panel, vbox, argv):
stdgui2.std_top_block.init (self, frame, panel, vbox, argv)

#Parametrs
tx_inter_rate = 400
trans_freq = 100e6
recv_freq = 100e6

#Create the USRP sink (transmitter)
ut = usrp.sink_c (0, tx_inter_rate)
dac_rate = ut.dac_rate()
sampl_rate = dac_rate / tx_inter_rate

#First choose the transmitting device
tx_sd = usrp.pick_tx_subdevice(ut)
m = usrp.determine_tx_mux_value(ut, tx_sd)
ut.set_mux(m)
t_subdev = usrp.selected_subdev(ut, tx_sd)
print “Using TX board %s” % (t_subdev.side_and_name(),)

#Transmit at the maximum possible gain
t_subdev.set_gain(t_subdev.gain_range()[1])

#Set the transmit frequency and check that it worked
r = ut.tune(t_subdev._which, t_subdev, trans_freq)

if not r:
sys.stderr.write(‘Failed to set RF transmit frequency\n’)
raise SystemExit

#Turn on the transmitter
t_subdev.set_enable(True)

#Connect the sink to a SIN source
src0 = gr.sig_source_c (sampl_rate, # sample rate
gr.GR_SIN_WAVE, # waveform type
3500, # frequency
16000, # max amplitude
0) # DC Offset

self.connect (src0, ut)

#---------------------------------------------------------------------------------
#Create the USRP Source (receiver)
ur = usrp.source_c(0)
adc_rate = ur.adc_rate()
rx_decim_rate = int(adc_rate // sampl_rate)
ur.set_decim_rate(rx_decim_rate)
print "Rx decim rate ", rx_decim_rate

#Choose the recieving device
rx_sd = usrp.pick_rx_subdevice(ur)
m = usrp.determine_rx_mux_value(ur, rx_sd)
ur.set_mux(m)
r_subdev = usrp.selected_subdev(ur, rx_sd)
print “Using RX board %s” % (r_subdev.side_and_name(),)

#Set the recieve frequency
r = ur.tune(r_subdev._which, r_subdev, recv_freq)

if not r:
sys.stderr.write(‘Failed to set RF recieve frequency\n’)
raise SystemExit

conv2 = gr.complex_to_float ()
cf = gr.complex_to_float()
self.connect (ur,conv2)

scope as final sink

self.foo = scopesink2.scope_sink_f(panel, title=“Received signal”,
sample_rate=sampl_rate,v_scale=5e3)
self.connect (conv2, (self.foo,0))
vbox.Add (self.foo.win, 1, wx.EXPAND)
self.foo1 = scopesink2.scope_sink_f(panel, title=“Transmitted signal”,
sample_rate=sampl_rate,v_scale=5e3)
self.connect (src0, cf, (self.foo1,0))
vbox.Add (self.foo1.win, 1, wx.EXPAND)

if name == ‘main’:
app = stdgui2.stdapp (wfm_scope, “WFM RX”)
app.MainLoop ()


#2

Hello,

I am trying to implement a transceiver (Full Duplex) with a Basix TX
board and TVRX board.

I generate a sine wave(3500 Hz) and transmit using Basix Tx at 100MHz.

I also want to tune the TVRX board to 100MHz and receive the same signal
and plot it on the scope in the GUI.

I tried the following code. But I did not get any received signal in the
scope.

Please let me know what could be the problem and the corrections needed
to make it work.

Thanks a lot.
Sivaram

#!/usr/bin/env python
from gnuradio import gr, usrp
from gnuradio.wxgui import stdgui2, scopesink2
import wx

class wfm_scope(stdgui2.std_top_block):
def init(self, frame, panel, vbox, argv):
stdgui2.std_top_block.init (self, frame, panel, vbox, argv)

#Parametrs
tx_inter_rate = 400
trans_freq = 100e6
recv_freq = 100e6

#Create the USRP sink (transmitter)
ut = usrp.sink_c (0, tx_inter_rate)
dac_rate = ut.dac_rate()
sampl_rate = dac_rate / tx_inter_rate

#First choose the transmitting device
tx_sd = usrp.pick_tx_subdevice(ut)
m = usrp.determine_tx_mux_value(ut, tx_sd)
ut.set_mux(m)
t_subdev = usrp.selected_subdev(ut, tx_sd)
print “Using TX board %s” % (t_subdev.side_and_name(),)

#Transmit at the maximum possible gain
t_subdev.set_gain(t_subdev.gain_range()[1])

#Set the transmit frequency and check that it worked
r = ut.tune(t_subdev._which, t_subdev, trans_freq)

if not r:
sys.stderr.write(‘Failed to set RF transmit frequency\n’)
raise SystemExit

#Turn on the transmitter
t_subdev.set_enable(True)

#Connect the sink to a SIN source
src0 = gr.sig_source_c (sampl_rate, # sample rate
gr.GR_SIN_WAVE, # waveform type
3500, # frequency
16000, # max amplitude
0) # DC Offset

self.connect (src0, ut)

#---------------------------------------------------------------------------------
#Create the USRP Source (receiver)
ur = usrp.source_c(0)
adc_rate = ur.adc_rate()
rx_decim_rate = int(adc_rate // sampl_rate)
ur.set_decim_rate(rx_decim_rate)
print "Rx decim rate ", rx_decim_rate

#Choose the recieving device
rx_sd = usrp.pick_rx_subdevice(ur)
m = usrp.determine_rx_mux_value(ur, rx_sd)
ur.set_mux(m)
r_subdev = usrp.selected_subdev(ur, rx_sd)
print “Using RX board %s” % (r_subdev.side_and_name(),)

#Set the recieve frequency
r = ur.tune(r_subdev._which, r_subdev, recv_freq)

if not r:
sys.stderr.write(‘Failed to set RF recieve frequency\n’)
raise SystemExit

conv2 = gr.complex_to_float ()
cf = gr.complex_to_float()
self.connect (ur,conv2)

scope as final sink

self.foo = scopesink2.scope_sink_f(panel, title=“Received signal”,
sample_rate=sampl_rate,v_scale=5e3)
self.connect (conv2, (self.foo,0))
vbox.Add (self.foo.win, 1, wx.EXPAND)
self.foo1 = scopesink2.scope_sink_f(panel, title=“Transmitted signal”,
sample_rate=sampl_rate,v_scale=5e3)
self.connect (src0, cf, (self.foo1,0))
vbox.Add (self.foo1.win, 1, wx.EXPAND)

if name == ‘main’:
app = stdgui2.stdapp (wfm_scope, “WFM RX”)
app.MainLoop ()


#3

On Wed, Feb 18, 2009 at 06:14:54PM +0530, Narayanan, Sivaramasubramanian
(R&T) wrote:

I generate a sine wave(3500 Hz) and transmit using Basix Tx at 100MHz.

I also want to tune the TVRX board to 100MHz and receive the same signal and
plot it on the scope in the GUI.

What exactly did you see? Did you try an FFT visualisation with
appropriate decimation? Your error and debugging procedure description
could be a bit more precise for others to help.
Do you have a spectrum analyser to see what’s happening? At 100 MHz,
you could even use a normal FM radio to pick up something (you might
want to use a different test signal, in that case).

MB