Hi
when I applied AM modulated signal to USRP from Signal Generator.
I can not getting the same modulating frequency.
Parameters are as.
RF Frequency = 900 MHz
Modulation Frequency=80KHz
Modulatio Rate=50%
I am using DBRX daughterboard:
The code is attached.
can any body check this code.
Thanks
#!/usr/bin/env python
from gnuradio import gr, gru, eng_notation, optfir
from gnuradio import audio
from gnuradio import usrp
from gnuradio import blks2
from gnuradio.eng_option import eng_option
from gnuradio.wxgui import slider, powermate
from gnuradio.wxgui import stdgui, fftsink, form,scopesink
from optparse import OptionParser
from usrpm import usrp_dbid
import sys
import math
import wx
def pick_subdevice(u):
return usrp.pick_subdev(u, (usrp_dbid.TV_RX_REV_2,
usrp_dbid.DBS_RX,
usrp_dbid.DBS_RX_REV_2_1,
usrp_dbid.BASIC_RX))
class rf_frontEnd(stdgui.gui_flow_graph):
def __init__(self,frame,panel,vbox,argv):
#stdgui2.std_top_block.__init__ (self,frame,panel,vbox,argv)
stdgui.gui_flow_graph.__init__(self,frame,panel,vbox,argv)
#--------------------------------------------------------------------------------
# User selects Target frequency
#--------------------------------------------------------------------------------
parser=OptionParser(option_class=eng_option)
parser.add_option("-f", "--freq", type="eng_float", default=2205e6,
help="set frequency to FREQ", metavar="FREQ")
(options, args) = parser.parse_args()
if len(args) != 0:
parser.print_help()
sys.exit(1)
#----------------------------------------------------------------------------------
self.frame = frame
self.panel = panel
self.freq = options.freq
# build graph
#self.connect(self.u,throttle)
self.u = usrp.source_c() # usrp is data source in complex format - 8 bytes
adc_rate = self.u.adc_rate() # ADC sampling rate- 64 MS/s
usrp_decim = 200 # must be between 8-256 even number only
self.u.set_decim_rate(usrp_decim) # set decimation rate of USRP
usrp_rate = adc_rate / usrp_decim # usp output rate 320 kS/s
chanfilt_decim = 1
rx_subdev_spec = pick_subdevice(self.u) # Autoselect Daughter Board
self.u.set_mux(usrp.determine_rx_mux_value(self.u, rx_subdev_spec))
self.subdev = usrp.selected_subdev(self.u, rx_subdev_spec)
print "Using RX d'board %s" % (self.subdev.side_and_name(),) # Displays side and name of DBSRX
self.set_freq(self.freq)
"""
Covert complex to real
"""
op = gr.complex_to_float()
self.connect(self.u,op)
#-----------Display Recieved signal: TIME DOMAIN-----------------------------------------------------------
scope = scopesink.scope_sink_f(self, panel, title="RECEIVED SIGNAL (REAL): TIME DOMAIN", sample_rate= usrp_rate)
vbox.Add(scope.win,4,wx.EXPAND)
self.connect(op,scope) #real bandpass signal to oscilloscope
# -----------------RF front end tuning----------------------------------
def set_freq(self, target_freq):
r = usrp.tune(self.u, 0, self.subdev, target_freq)
if r: print " Tune to IF freq success %s" % (target_freq)
#----RUN THE SOFTWARE------------------------------------------------------------
if __name__ == '__main__':
app = stdgui.stdapp (rf_frontEnd, "ESEU Receiver")
app.MainLoop ()
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