I have tried transmitting an analog signal from one USRP2 to another, but
when I run usrp2_fft.py on the rx computer, there is no receive signal. The
analog signal is supposed to be two tones at 350 and 440 HZ transmitted at
2.6GHz. Can anyone help me figure out what I am doing wrong?
I have tried using GRC, but at the most up to date version does not work
with Fedora, which is the OS that I have to use, this is for a research
project with a professor at my university, and the mandate is to use Fedora,
this does not look like it will change in the near future.
Alex
#!/usr/bin/env python
from gnuradio import gr
from gnuradio import usrp2
from gnuradio import audio
from gnuradio import eng_notation
from gnuradio.eng_option import eng_option
from optparse import OptionParser
import math
def build_graph(options, args):
#These are set to 440 and 350
freq0 = options.waveform_freq
freq1 = options.waveform2_freq
#This is the USRP2
sink1 = usrp2.sink_32fc(options.interface,options.mac_addr)
DACRate = sink1.dac_rate()
interp = options.interp
amp = .5
scRate = 50e3
cFreq = 1/16*scRate
tWidt = 1/16*scRate
tFreq = 2.6e9
#Sets the tranmsmit center frequency
tx = sink1.set_center_freq(tFreq)
print tx
g = sink1.set_gain(1)
print g
fg = gr.top_block()
ethRate = DACRate/interp
#Frequency generators
src0 = gr.sig_source_f(scRate,gr.GR_SIN_WAVE,int(freq0),amp)
src1 = gr.sig_source_f(scRate,gr.GR_SIN_WAVE,int(freq1),amp)
add0 = gr.add_ff()
#Converts the input samples to complex to transmit to USRP2
f2c = gr.float_to_complex()
#Creates filter for interpolator
chanCoeffs = gr.firdes.low_pass(1.0, scRate, 1000, 3000, gr.firdes.WIN_HAMMING)
print ethRate/scRate
print DACRate
#Upsamples the input stream to transmit to the USRP2
interp = gr.interp_fir_filter_ccf(int(ethRate/scRate),chanCoeffs)
#Plays the two tones over speakers
sink0 = audio.sink(int(scRate))
fg.connect((src0, 0), (add0, 0))
fg.connect((src1, 0), (add0, 1))
fg.connect(add0, sink0)
fg.connect(add0, f2c)
fg.connect(f2c, interp)
fg.connect(interp, sink1)
return fg
def get_options():
usage="%prog: [options]"
parser = OptionParser(option_class=eng_option, usage=usage)
parser.add_option("-e", "--interface", type="string", default="eth0",
help="Use specified Ethernet interface [default=%default]")
parser.add_option("-m", "--mac-addr", type="string", default="",
help="Use USRP2 at specified MAC address [default=None]")
parser.add_option("-i", "--interp", type="int", default=16, metavar="INTERP",
help="Set FPGA interpolation rate of INTERP [default=%default]")
parser.add_option("-f", "--tx-freq", type="eng_float", default=None,
help="Set carrier frequency to FREQ [default=mid-point]", metavar="FREQ")
parser.add_option("--lo-offset", type="eng_float", default=None,
help="set daughterboard LO offset to OFFSET [default=hw default]")
parser.add_option("-g", "--gain", type="eng_float", default=None,
help="Set TX gain to GAIN [default=mid-point]")
parser.add_option("-w", "--waveform-freq", type="eng_float", default=440,
help="Set baseband waveform frequency to FREQ [default=%default]")
parser.add_option("-x", "--waveform2-freq", type="eng_float", default=350,
help="Set 2nd waveform frequency to FREQ [default=%default]")
parser.add_option("--sine", dest="type", action="store_const", const=gr.GR_SIN_WAVE,
help="Generate a carrier modulated by a complex sine wave", default=gr.GR_SIN_WAVE)
parser.add_option("--const", dest="type", action="store_const", const=gr.GR_CONST_WAVE,
help="Generate a constant carrier")
parser.add_option("--offset", type="eng_float", default=0,
help="Set waveform phase offset to OFFSET [default=%default]")
parser.add_option("--gaussian", dest="type", action="store_const", const=gr.GR_GAUSSIAN,
help="Generate Gaussian random output")
parser.add_option("--uniform", dest="type", action="store_const", const=gr.GR_UNIFORM,
help="Generate Uniform random output")
parser.add_option("--2tone", dest="type", action="store_const", const="2tone",
help="Generate Two Tone signal for IMD testing")
parser.add_option("--sweep", dest="type", action="store_const", const="sweep",
help="Generate a swept sine wave")
parser.add_option("-a", "--amplitude", type="eng_float", default=0.1,
help="Set output amplitude to AMPL (0.0-1.0) [default=%default]", metavar="AMPL")
parser.add_option("-v", "--verbose", action="store_true", default=False,
help="Use verbose console output [default=%default]")
(options, args) = parser.parse_args()
return (options, args)
if __name__=="__main__":
(options, args) = get_options()
fg = build_graph(options, args)
fg.start()
raw_input('Press enter to quit: ')
fg.stop()
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