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https://github.com/brmlab/osmo-tetra.git
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add frequency and gain controls to rtlsdr receiver
This commit is contained in:
Dimitri Stolnikov
parent
2037ebeac6
commit
582acdf444
1 changed files with 115 additions and 38 deletions
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@ -2,12 +2,14 @@
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# Copyright 2012 Dimitri Stolnikov <horiz0n@gmx.net>
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# Call it with
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# src$ ./demod/python/rtlsdr-tetra_demod_fft.py -s 1.8e6 -f 394.6e6 -g -1 -o /dev/stdout | ./float_to_bits /dev/stdin /dev/stdout | ./tetra-rx /dev/stdin
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# Usage:
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# src$ ./demod/python/rtlsdr-tetra_demod_fft.py -o /dev/stdout | ./float_to_bits /dev/stdin /dev/stdout | ./tetra-rx /dev/stdin
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#
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# Adjust the center frequency (-f) and gain (-g) according to your needs.
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# Use left click in Full Spectrum window to roughly select a TETRA carrier.
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# Use left click to fine tune the carrier by clicking on the left or right side of the spectrum.
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# Use left click in Wideband Spectrum window to roughly select a TETRA carrier.
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# In Wideband Spectrum you can also tune by 1/4 of the bandwidth by clicking on the rightmost/leftmost spectrum side.
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# Use left click in Channel Spectrum windows to fine tune the carrier by clicking on the left or right side of the spectrum.
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import sys
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import math
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@ -15,6 +17,7 @@ from gnuradio import gr, gru, audio, eng_notation, blks2, optfir
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from gnuradio import audio
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from gnuradio.eng_option import eng_option
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from gnuradio.wxgui import fftsink2
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from gnuradio.wxgui import forms
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from grc_gnuradio import wxgui as grc_wxgui
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from optparse import OptionParser
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import osmosdr
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@ -33,37 +36,42 @@ class top_block(grc_wxgui.top_block_gui):
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options = get_options()
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self.ifreq = options.frequency
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self.rfgain = options.gain
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self.src = osmosdr.source_c()
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self.src.set_center_freq(options.frequency)
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self.src.set_center_freq(self.ifreq)
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self.src.set_sample_rate(int(options.sample_rate))
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if options.gain is None:
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if self.rfgain is None:
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self.src.set_gain_mode(1)
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self.iagc = 1
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self.rfgain = 0
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else:
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self.iagc = 0
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self.src.set_gain_mode(0)
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self.src.set_gain(options.gain)
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self.src.set_gain(self.rfgain)
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# may differ from the requested rate
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sample_rate = self.src.get_sample_rate()
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symbol_rate = 18000
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sps = 2 # output rate will be 36,000
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new_sample_rate = symbol_rate * sps
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out_sample_rate = symbol_rate * sps
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options.low_pass = options.low_pass / 2.0
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taps = gr.firdes.low_pass(1.0, sample_rate, options.low_pass, options.low_pass * 0.2, gr.firdes.WIN_HANN)
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first_decim = 10
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self.offset = 0
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taps = gr.firdes.low_pass(1.0, sample_rate, options.low_pass, options.low_pass * 0.2, gr.firdes.WIN_HANN)
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self.tuner = gr.freq_xlating_fir_filter_ccf(first_decim, taps, self.offset, sample_rate)
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sys.stderr.write("sample rate: %d\n" % (sample_rate))
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self.demod = cqpsk.cqpsk_demod(
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samples_per_symbol = sps,
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samples_per_symbol = sps,
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excess_bw=0.35,
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costas_alpha=0.03,
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gain_mu=0.05,
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@ -74,29 +82,98 @@ class top_block(grc_wxgui.top_block_gui):
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self.output = gr.file_sink(gr.sizeof_float, options.output_file)
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rerate = float(sample_rate / float(first_decim)) / float(new_sample_rate)
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rerate = float(sample_rate / float(first_decim)) / float(out_sample_rate)
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sys.stderr.write("resampling factor: %f\n" % rerate)
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#self.resamp = gr.fractional_interpolator_cc(0, rerate)
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self.resamp = blks2.pfb_arb_resampler_ccf(1 / rerate)
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if rerate.is_integer():
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sys.stderr.write("using pfb decimator\n")
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self.resamp = blks2.pfb_decimator_ccf(int(rerate))
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else:
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sys.stderr.write("using pfb resampler\n")
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self.resamp = blks2.pfb_arb_resampler_ccf(1 / rerate)
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self.connect(self.src, self.tuner, self.resamp, self.demod, self.output)
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def set_ifreq(ifreq):
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self.ifreq = ifreq
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self._ifreq_text_box.set_value(self.ifreq)
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self.src.set_center_freq(self.ifreq)
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self._ifreq_text_box = forms.text_box(
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parent=self.GetWin(),
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value=self.ifreq,
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callback=set_ifreq,
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label="Center Frequency",
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converter=forms.float_converter(),
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)
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self.Add(self._ifreq_text_box)
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def set_iagc(iagc):
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self.iagc = iagc
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self._agc_check_box.set_value(self.iagc)
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self.src.set_gain_mode(self.iagc, 0)
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self.src.set_gain(0 if self.iagc == 1 else self.rfgain, 0)
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self._agc_check_box = forms.check_box(
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parent=self.GetWin(),
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value=self.iagc,
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callback=set_iagc,
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label="Automatic Gain",
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true=1,
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false=0,
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)
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self.Add(self._agc_check_box)
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def set_rfgain(rfgain):
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self.rfgain = rfgain
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self._rfgain_slider.set_value(self.rfgain)
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self._rfgain_text_box.set_value(self.rfgain)
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self.src.set_gain(0 if self.iagc == 1 else self.rfgain, 0)
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_rfgain_sizer = wx.BoxSizer(wx.VERTICAL)
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self._rfgain_text_box = forms.text_box(
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parent=self.GetWin(),
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sizer=_rfgain_sizer,
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value=self.rfgain,
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callback=set_rfgain,
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label="RF Gain",
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converter=forms.float_converter(),
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proportion=0,
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)
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self._rfgain_slider = forms.slider(
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parent=self.GetWin(),
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sizer=_rfgain_sizer,
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value=self.rfgain,
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callback=set_rfgain,
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minimum=0,
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maximum=50,
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num_steps=200,
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style=wx.SL_HORIZONTAL,
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cast=float,
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proportion=1,
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)
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self.Add(_rfgain_sizer)
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def fftsink2_callback(x, y):
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sys.stderr.write("selected channel at offset: %d Hz\n" % x)
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self.offset = -x
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self.tuner.set_center_freq(self.offset)
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if abs(x / (sample_rate / 2)) > 0.9:
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set_ifreq(self.ifreq + x / 2)
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else:
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sys.stderr.write("coarse tuned to: %d Hz\n" % x)
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self.offset = -x
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self.tuner.set_center_freq(self.offset)
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self.scope = fftsink2.fft_sink_c(self.GetWin(),
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title="Full Spectrum (click to coarse tune)",
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fft_size=1024,
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sample_rate=sample_rate,
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ref_scale=2.0,
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ref_level=-30,
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y_divs=10,
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fft_rate=10,
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average=False,
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avg_alpha=0.6)
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title="Wideband Spectrum (click to coarse tune)",
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fft_size=1024,
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sample_rate=sample_rate,
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ref_scale=2.0,
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ref_level=0,
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y_divs=10,
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fft_rate=10,
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average=False,
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avg_alpha=0.6)
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self.Add(self.scope.win)
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self.scope.set_callback(fftsink2_callback)
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@ -104,20 +181,20 @@ class top_block(grc_wxgui.top_block_gui):
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self.connect(self.src, self.scope)
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def fftsink2_callback2(x, y):
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sys.stderr.write("fine tuning channel: %d Hz\n" % x)
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self.offset = self.offset - (x / 10)
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self.offset = self.offset - (x / 10)
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sys.stderr.write("fine tuned to: %d Hz\n" % self.offset)
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self.tuner.set_center_freq(self.offset)
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self.scope2 = fftsink2.fft_sink_c(self.GetWin(),
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title="Narrow Spectrum (click to fine tune)",
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fft_size=1024,
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sample_rate=new_sample_rate, #sample_rate / first_decim,
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ref_scale=2.0,
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ref_level=-30,
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y_divs=10,
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fft_rate=10,
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average=False,
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avg_alpha=0.6)
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title="Channel Spectrum (click to fine tune)",
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fft_size=1024,
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sample_rate=out_sample_rate,
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ref_scale=2.0,
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ref_level=-20,
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y_divs=10,
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fft_rate=10,
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average=False,
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avg_alpha=0.6)
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self.Add(self.scope2.win)
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self.scope2.set_callback(fftsink2_callback2)
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@ -129,7 +206,7 @@ def get_options():
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parser.add_option("-s", "--sample-rate", type="eng_float", default=1800000,
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help="set receiver sample rate (default 1800000)")
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parser.add_option("-f", "--frequency", type="eng_float", default=394.6e9,
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parser.add_option("-f", "--frequency", type="eng_float", default=394.6e6,
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help="set receiver center frequency")
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parser.add_option("-g", "--gain", type="eng_float", default=None,
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help="set receiver gain")
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