usrp_wfm_rcv_sca.py

这是用python语言写的一个数字广播的信号处理工具包。利用它

        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 = fftsink2.fft_sink_c(self.panel, title="Data from USRP",
                                               fft_size=512, sample_rate=usrp_rate,
					       ref_scale=32768.0, ref_level=0, y_divs=12)
            self.connect (self.u, self.src_fft)
            vbox.Add (self.src_fft.win, 4, wx.EXPAND)

        if 1:
            post_demod_fft = fftsink2.fft_sink_f(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 = fftsink2.fft_sink_f(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 = fftsink2.fft_sink_f (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 = stdgui2.stdapp (wfm_rx_sca_block, "USRP WFM SCA RX")
    app.MainLoop ()