From: eb Date: Sun, 14 Jan 2007 20:40:45 +0000 (+0000) Subject: New usrp_wfm_rcv_sca.py example from Eric A. Cottrell (WB1HBHU) X-Git-Url: https://git.gag.com/?a=commitdiff_plain;h=e67d15bded325ad7b68a95d632b6fd4ae9115cc9;p=debian%2Fgnuradio New usrp_wfm_rcv_sca.py example from Eric A. Cottrell (WB1HBHU) git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@4276 221aa14e-8319-0410-a670-987f0aec2ac5 --- diff --git a/gnuradio-examples/python/usrp/Makefile.am b/gnuradio-examples/python/usrp/Makefile.am index 1b7f8133..f179c15b 100644 --- a/gnuradio-examples/python/usrp/Makefile.am +++ b/gnuradio-examples/python/usrp/Makefile.am @@ -47,9 +47,10 @@ EXTRA_DIST = \ usrp_spectrum_sense.py \ usrp_tv_rcv_nogui.py \ usrp_tv_rcv.py \ - usrp_wfm_rcv2_nogui.py \ + usrp_wfm_rcv.py \ usrp_wfm_rcv_nogui.py \ usrp_wfm_rcv_pll.py \ - usrp_wfm_rcv.py \ + usrp_wfm_rcv_sca.py \ + usrp_wfm_rcv2_nogui.py \ usrp_wxapt_rcv.py \ wfm_rcv_file.py diff --git a/gnuradio-examples/python/usrp/usrp_wfm_rcv_sca.py b/gnuradio-examples/python/usrp/usrp_wfm_rcv_sca.py new file mode 100644 index 00000000..640ffe87 --- /dev/null +++ b/gnuradio-examples/python/usrp/usrp_wfm_rcv_sca.py @@ -0,0 +1,399 @@ +#!/usr/bin/env python +# +# Copyright 2006,2007 Free Software Foundation, Inc. +# +# This file is part of GNU Radio +# +# GNU Radio is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2, or (at your option) +# any later version. +# +# GNU Radio is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License along +# with this program; if not, write to the Free Software Foundation, Inc., +# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +# + +""" +Here is a bit of code that will receive SCA analog subcarriers of FM +Broadcast Stations using the USRP. It is a modified version of +usrp_wfm_rcv.py. + +Common SCA frequencies are 67 kHz and 92 kHz. SCA is used for Reading +Services for the Blind, Background Music, Foreign Language Services, and +other services. Remember you may hear static when tuned to a FM station +because this code only outputs SCA audio. + +The USRP gain is critical for good decoding. Adjust for minimum noise. + I use the Post FM Demod FFT to check for SCA subcarriers and to adjust +the USRP gain for the lowest noise floor. The stereo pilot at 19 KHz, +the stereo difference signal around 38 KHz, and RDS at 57 KHz are also +displayed on the Post FM Demod FFT if present. + +The range below 67 kHz is used for SCA only when Stereo is not used. + +The SCA recieve range is not as far as the main FM carrier receive range +so tune in strong local stations first. + +I tried to comment the code with the various parameters. There seems to +be several choices for a couple of them. I coded the common ones I see +here. + +In the local area there are a couple of stations using digital SCA. +These look similar to narrow DRM signals and I wonder if they are using +OFDM. +""" + + +from gnuradio import gr, gru, eng_notation, optfir +from gnuradio import audio +from gnuradio import usrp +from gnuradio import blks +from gnuradio.blksimpl.fm_emph import fm_deemph +from gnuradio.eng_option import eng_option +from gnuradio.wxgui import slider, powermate +from gnuradio.wxgui import stdgui, fftsink, form +from optparse import OptionParser +import usrp_dbid +import sys +import math +import wx + +def pick_subdevice(u): + """ + The user didn't specify a subdevice on the command line. + Try for one of these, in order: TV_RX, BASIC_RX, whatever is on side A. + + @return a subdev_spec + """ + return usrp.pick_subdev(u, (usrp_dbid.TV_RX, + usrp_dbid.TV_RX_REV_2, + usrp_dbid.BASIC_RX)) + + +class wfm_rx_sca_graph (stdgui.gui_flow_graph): + def __init__(self,frame,panel,vbox,argv): + stdgui.gui_flow_graph.__init__ (self,frame,panel,vbox,argv) + + parser=OptionParser(option_class=eng_option) + parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=None, + help="select USRP Rx side A or B (default=A)") + parser.add_option("-f", "--freq", type="eng_float", default=100.1e6, + help="set frequency to FREQ", metavar="FREQ") + parser.add_option("-g", "--gain", type="eng_float", default=40, + help="set gain in dB (default is midpoint)") + parser.add_option("-V", "--volume", type="eng_float", default=None, + help="set volume (default is midpoint)") + parser.add_option("-O", "--audio-output", type="string", default="", + help="pcm device name. E.g., hw:0,0 or surround51 or /dev/dsp") + + (options, args) = parser.parse_args() + if len(args) != 0: + parser.print_help() + sys.exit(1) + + self.frame = frame + self.panel = panel + + self.vol = 0 + self.state = "FREQ" + self.freq = 0 + + # build graph + + self.u = usrp.source_c() # usrp is data source + + adc_rate = self.u.adc_rate() # 64 MS/s + usrp_decim = 200 + self.u.set_decim_rate(usrp_decim) + usrp_rate = adc_rate / usrp_decim # 320 kS/s + chanfilt_decim = 1 + demod_rate = usrp_rate / chanfilt_decim + sca_chanfilt_decim = 5 + sca_demod_rate = demod_rate / sca_chanfilt_decim #64 kHz + audio_decimation = 2 + audio_rate = sca_demod_rate / audio_decimation # 32 kHz + + if options.rx_subdev_spec is None: + options.rx_subdev_spec = pick_subdevice(self.u) + + self.u.set_mux(usrp.determine_rx_mux_value(self.u, options.rx_subdev_spec)) + self.subdev = usrp.selected_subdev(self.u, options.rx_subdev_spec) + print "Using RX d'board %s" % (self.subdev.side_and_name(),) + + #Create filter to get main FM Channel we want + chan_filt_coeffs = optfir.low_pass (1, # gain + usrp_rate, # sampling rate + 100e3, # passband cutoff + 140e3, # stopband cutoff + 0.1, # passband ripple + 60) # stopband attenuation + #print len(chan_filt_coeffs) + chan_filt = gr.fir_filter_ccf (chanfilt_decim, chan_filt_coeffs) + + #Create demodulator block for Main FM Channel + max_dev = 75e3 + fm_demod_gain = demod_rate/(2*math.pi*max_dev) + self.fm_demod = gr.quadrature_demod_cf (fm_demod_gain) + + # Note - deemphasis is not applied to the Main FM Channel as main audio is not decoded + + # SCA Devation is 10% of carrier but some references say 20% if mono with one SCA (6 KHz seems typical) + max_sca_dev = 6e3 + + # Create filter to get SCA channel we want + sca_chan_coeffs = gr.firdes.low_pass (1.0, # gain + demod_rate, # sampling rate + max_sca_dev, # low pass cutoff freq + max_sca_dev/3, # width of trans. band + gr.firdes.WIN_HANN) # filter type + + self.ddc = gr.freq_xlating_fir_filter_fcf(sca_chanfilt_decim, # decimation rate + sca_chan_coeffs, # taps + 0, # frequency translation amount (Gets set by the UI) + demod_rate) # input sample rate + + #Create demodulator block for SCA Channel + sca_demod_gain = sca_demod_rate/(2*math.pi*max_sca_dev) + self.fm_demod_sca = gr.quadrature_demod_cf (sca_demod_gain) + + + # SCA analog audio is bandwidth limited to 5 KHz + max_sca_audio_freq = 5.0e3 + # SCA analog deephasis is 150 uS (75 uS may be used) + sca_tau = 150e-6 + + # compute FIR filter taps for SCA audio filter + audio_coeffs = gr.firdes.low_pass (1.0, # gain + sca_demod_rate, # sampling rate + max_sca_audio_freq, # low pass cutoff freq + max_sca_audio_freq/2.5, # width of trans. band + gr.firdes.WIN_HAMMING) + + # input: float; output: float + self.audio_filter = gr.fir_filter_fff (audio_decimation, audio_coeffs) + + # Create deemphasis block that is applied after SCA demodulation + self.deemph = fm_deemph (self, audio_rate, sca_tau) + + self.volume_control = gr.multiply_const_ff(self.vol) + + # sound card as final sink + audio_sink = audio.sink (int (audio_rate), + options.audio_output, + False) # ok_to_block + + # now wire it all together + self.connect (self.u, chan_filt, self.fm_demod, self.ddc, self.fm_demod_sca) + self.connect (self.fm_demod_sca, self.audio_filter, self.deemph, self.volume_control, audio_sink) + + self._build_gui(vbox, usrp_rate, demod_rate, sca_demod_rate, audio_rate) + + if options.gain is None: + # if no gain was specified, use the mid-point in dB + g = self.subdev.gain_range() + options.gain = float(g[0]+g[1])/2 + + if options.volume is None: + g = self.volume_range() + options.volume = float(g[0]+g[1])/2 + + if abs(options.freq) < 1e6: + options.freq *= 1e6 + + # set initial values + + self.set_gain(options.gain) + self.set_vol(options.volume) + if not(self.set_freq(options.freq)): + self._set_status_msg("Failed to set initial frequency") + self.set_sca_freq(67000) # A common SCA Frequency + + + def _set_status_msg(self, msg, which=0): + self.frame.GetStatusBar().SetStatusText(msg, which) + + + def _build_gui(self, vbox, usrp_rate, demod_rate, sca_demod_rate, audio_rate): + + def _form_set_freq(kv): + return self.set_freq(kv['freq']) + + def _form_set_sca_freq(kv): + return self.set_sca_freq(kv['sca_freq']) + + if 1: + self.src_fft = fftsink.fft_sink_c (self, self.panel, title="Data from USRP", + fft_size=512, sample_rate=usrp_rate) + self.connect (self.u, self.src_fft) + vbox.Add (self.src_fft.win, 4, wx.EXPAND) + + if 1: + post_demod_fft = fftsink.fft_sink_f (self, self.panel, title="Post FM Demod", + fft_size=2048, sample_rate=demod_rate, + y_per_div=10, ref_level=0) + self.connect (self.fm_demod, post_demod_fft) + vbox.Add (post_demod_fft.win, 4, wx.EXPAND) + + if 0: + post_demod_sca_fft = fftsink.fft_sink_f (self, self.panel, title="Post SCA Demod", + fft_size=1024, sample_rate=sca_demod_rate, + y_per_div=10, ref_level=0) + self.connect (self.fm_demod_sca, post_demod_sca_fft) + vbox.Add (post_demod_sca_fft.win, 4, wx.EXPAND) + + if 0: + post_deemph_fft = fftsink.fft_sink_f (self, self.panel, title="Post SCA Deemph", + fft_size=512, sample_rate=audio_rate, + y_per_div=10, ref_level=-20) + self.connect (self.deemph, post_deemph_fft) + vbox.Add (post_deemph_fft.win, 4, wx.EXPAND) + + + # control area form at bottom + self.myform = myform = form.form() + + hbox = wx.BoxSizer(wx.HORIZONTAL) + hbox.Add((5,0), 0) + myform['freq'] = form.float_field( + parent=self.panel, sizer=hbox, label="Freq", weight=1, + callback=myform.check_input_and_call(_form_set_freq, self._set_status_msg)) + + hbox.Add((5,0), 0) + myform['freq_slider'] = \ + form.quantized_slider_field(parent=self.panel, sizer=hbox, weight=3, + range=(87.9e6, 108.1e6, 0.1e6), + callback=self.set_freq) + hbox.Add((5,0), 0) + vbox.Add(hbox, 0, wx.EXPAND) + + hbox = wx.BoxSizer(wx.HORIZONTAL) + hbox.Add((5,0), 0) + myform['sca_freq'] = form.float_field( + parent=self.panel, sizer=hbox, label="SCA", weight=1, + callback=myform.check_input_and_call(_form_set_sca_freq, self._set_status_msg)) + + hbox.Add((5,0), 0) + myform['sca_freq_slider'] = \ + form.quantized_slider_field(parent=self.panel, sizer=hbox, weight=3, + range=(38e3, 100e3, 1.0e3), + callback=self.set_sca_freq) + hbox.Add((5,0), 0) + vbox.Add(hbox, 0, wx.EXPAND) + + hbox = wx.BoxSizer(wx.HORIZONTAL) + hbox.Add((5,0), 0) + + myform['volume'] = \ + form.quantized_slider_field(parent=self.panel, sizer=hbox, label="Volume", + weight=3, range=self.volume_range(), + callback=self.set_vol) + hbox.Add((5,0), 1) + + myform['gain'] = \ + form.quantized_slider_field(parent=self.panel, sizer=hbox, label="Gain", + weight=3, range=self.subdev.gain_range(), + callback=self.set_gain) + hbox.Add((5,0), 0) + vbox.Add(hbox, 0, wx.EXPAND) + + try: + self.knob = powermate.powermate(self.frame) + self.rot = 0 + powermate.EVT_POWERMATE_ROTATE (self.frame, self.on_rotate) + powermate.EVT_POWERMATE_BUTTON (self.frame, self.on_button) + except: + print "FYI: No Powermate or Contour Knob found" + + + def on_rotate (self, event): + self.rot += event.delta + if (self.state == "FREQ"): + if self.rot >= 3: + self.set_freq(self.freq + .1e6) + self.rot -= 3 + elif self.rot <=-3: + self.set_freq(self.freq - .1e6) + self.rot += 3 + else: + step = self.volume_range()[2] + if self.rot >= 3: + self.set_vol(self.vol + step) + self.rot -= 3 + elif self.rot <=-3: + self.set_vol(self.vol - step) + self.rot += 3 + + def on_button (self, event): + if event.value == 0: # button up + return + self.rot = 0 + if self.state == "FREQ": + self.state = "VOL" + else: + self.state = "FREQ" + self.update_status_bar () + + + def set_vol (self, vol): + g = self.volume_range() + self.vol = max(g[0], min(g[1], vol)) + self.volume_control.set_k(10**(self.vol/10)) + self.myform['volume'].set_value(self.vol) + self.update_status_bar () + + def set_freq(self, target_freq): + """ + Set the center frequency we're interested in. + + @param target_freq: frequency in Hz + @rypte: bool + + Tuning is a two step process. First we ask the front-end to + tune as close to the desired frequency as it can. Then we use + the result of that operation and our target_frequency to + determine the value for the digital down converter. + """ + r = usrp.tune(self.u, 0, self.subdev, target_freq) + + if r: + self.freq = target_freq + self.myform['freq'].set_value(target_freq) # update displayed value + self.myform['freq_slider'].set_value(target_freq) # update displayed value + self.update_status_bar() + self._set_status_msg("OK", 0) + return True + + self._set_status_msg("Failed", 0) + return False + + def set_sca_freq(self, target_sca_freq): + + self.ddc.set_center_freq(-target_sca_freq) + self.myform['sca_freq'].set_value(target_sca_freq) # update displayed value + self.myform['sca_freq_slider'].set_value(target_sca_freq) # update displayed value + self.update_status_bar() + self._set_status_msg("OK", 0) + return True + + def set_gain(self, gain): + self.myform['gain'].set_value(gain) # update displayed value + self.subdev.set_gain(gain) + + def update_status_bar (self): + msg = "Volume:%r Setting:%s" % (self.vol, self.state) + self._set_status_msg(msg, 1) + self.src_fft.set_baseband_freq(self.freq) + + def volume_range(self): + return (-20.0, 0.0, 0.5) + + +if __name__ == '__main__': + app = stdgui.stdapp (wfm_rx_sca_graph, "USRP WFM SCA RX") + app.MainLoop ()