Hello, everyone
I dug up the wfm_rcv_gui.py example file in order to penetrate the principle of
GNURadio. But I have 2 questions about it:
1, there is a digital downconverter at the receiver, the function of down
converting the signal is performed by the FPGA or the software on PC?
2, if it is done by FPGA, how is the code transmitted to the FPGA? I mean, the
code should be written using VHDL or Verilog, but now the code is compiled
using Python! How is this transformation done?
Thank u!!!
#!/usr/bin/env python
from gnuradio import gr, eng_notation
from gnuradio import audio
from gnuradio import usrp
from gnuradio import blks
from gnuradio.eng_option import eng_option
from optparse import OptionParser
import sys
import math
from gnuradio.wxgui import stdgui, fftsink
import wx
class wfm_rx_graph (stdgui.gui_flow_graph):
def __init__(self,frame,panel,vbox,argv):
stdgui.gui_flow_graph.__init__ (self,frame,panel,vbox,argv)
IF_freq = parseargs(argv[1:])
adc_rate = 64e6
decim = 250
quad_rate = adc_rate / decim # 256 kHz
audio_decimation = 8
audio_rate = quad_rate / audio_decimation # 32 kHz
# usrp is data source
src = usrp.source_c (0, decim)
src.set_rx_freq (0, IF_freq)[email protected]
src.set_pga(0,20)
guts = blks.wfm_rcv (self, quad_rate, audio_decimation)
# sound card as final sink
audio_sink = audio.sink (int (audio_rate))
# now wire it all together
self.connect (src, guts)
self.connect (guts, (audio_sink, 0))
if 1:
pre_demod, fft_win1 = \
fftsink.make_fft_sink_c (self, panel, "Pre-Demodulation",
512, quad_rate)
self.connect (src, pre_demod)
vbox.Add (fft_win1, 1, wx.EXPAND)
if 1:
post_deemph, fft_win3 = \
fftsink.make_fft_sink_f (self, panel, "With Deemph",
512, quad_rate, -60, 20)
self.connect (guts.deemph, post_deemph)
vbox.Add (fft_win3, 1, wx.EXPAND)
if 1:
post_filt, fft_win4 = \
fftsink.make_fft_sink_f (self, panel, "Post Filter",
512, audio_rate, -60, 20)
self.connect (guts.audio_filter, post_filt)
vbox.Add (fft_win4, 1, wx.EXPAND)
def parseargs (args):
nargs = len (args)
if nargs == 1:
freq1 = float (args[0]) * 1e6
else:
sys.stderr.write ('usage: wfm_rcv freq1\n')
sys.exit (1)
return freq1 - 128e6
if __name__ == '__main__':
app = stdgui.stdapp (wfm_rx_graph, "WFM RX")
app.MainLoop ()
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