add frequency and gain controls to rtlsdr receiver

src/demod/python/rtlsdr-tetra_demod_fft.py

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