fftsink2.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

        self.fftsink = fftsink
        #init panel and plot 
        wx.Panel.__init__(self, parent, -1)                  
        self.plot = plot.PlotCanvas(self, id, pos, size, style, name)       
        #setup the box with plot and controls
        self.control_panel = control_panel(self)
        main_box = wx.BoxSizer (wx.HORIZONTAL)
        main_box.Add (self.plot, 1, wx.EXPAND)
        main_box.Add (self.control_panel, 0, wx.EXPAND)
        self.SetSizerAndFit(main_box)
        
        self.peak_hold = False
        self.peak_vals = None
        
        self.plot.SetEnableGrid (True)
        # self.SetEnableZoom (True)
        # self.SetBackgroundColour ('black')
        
        self.build_popup_menu()
        self.set_baseband_freq(0.0)
                
        EVT_DATA_EVENT (self, self.set_data)
        wx.EVT_CLOSE (self, self.on_close_window)
        self.plot.Bind(wx.EVT_RIGHT_UP, self.on_right_click)
        self.plot.Bind(wx.EVT_MOTION, self.evt_motion)
        
        self.input_watcher = input_watcher(fftsink.msgq, fftsink.fft_size, self)

    def set_scale(self, freq):
        x = max(abs(self.fftsink.sample_rate), abs(self.fftsink.baseband_freq))        
        if x >= 1e9:
            self._scale_factor = 1e-9
            self._units = "GHz"
            self._format = "%3.6f"
        elif x >= 1e6:
            self._scale_factor = 1e-6
            self._units = "MHz"
            self._format = "%3.3f"
        else:
            self._scale_factor = 1e-3
            self._units = "kHz"
            self._format = "%3.3f"

    def set_baseband_freq(self, baseband_freq):
        if self.peak_hold:
            self.peak_vals = None
        self.set_scale(baseband_freq)
        self.fftsink.set_baseband_freq(baseband_freq)
        
    def on_close_window (self, event):
        print "fft_window:on_close_window"
        self.keep_running = False


    def set_data (self, evt):
        dB = evt.data
        L = len (dB)

        if self.peak_hold:
            if self.peak_vals is None:
                self.peak_vals = dB
            else:
                self.peak_vals = numpy.maximum(dB, self.peak_vals)

        if self.fftsink.input_is_real:     # only plot 1/2 the points
            x_vals = ((numpy.arange (L/2) * (self.fftsink.sample_rate 
                       * self._scale_factor / L))
                      + self.fftsink.baseband_freq * self._scale_factor)
            self._points = numpy.zeros((len(x_vals), 2), numpy.float64)
            self._points[:,0] = x_vals
            self._points[:,1] = dB[0:L/2]
            if self.peak_hold:
                self._peak_points = numpy.zeros((len(x_vals), 2), numpy.float64)
                self._peak_points[:,0] = x_vals
                self._peak_points[:,1] = self.peak_vals[0:L/2]
        else:
            # the "negative freqs" are in the second half of the array
            x_vals = ((numpy.arange (-L/2, L/2)
                       * (self.fftsink.sample_rate * self._scale_factor / L))
                      + self.fftsink.baseband_freq * self._scale_factor)
            self._points = numpy.zeros((len(x_vals), 2), numpy.float64)
            self._points[:,0] = x_vals
            self._points[:,1] = numpy.concatenate ((dB[L/2:], dB[0:L/2]))
            if self.peak_hold:
                self._peak_points = numpy.zeros((len(x_vals), 2), numpy.float64)
                self._peak_points[:,0] = x_vals
                self._peak_points[:,1] = numpy.concatenate ((self.peak_vals[L/2:], self.peak_vals[0:L/2]))

        lines = [plot.PolyLine (self._points, colour='BLUE'),]
        if self.peak_hold:
            lines.append(plot.PolyLine (self._peak_points, colour='GREEN'))

        graphics = plot.PlotGraphics (lines,
                                      title=self.fftsink.title,
                                      xLabel = self._units, yLabel = "dB")
        x_range = x_vals[0], x_vals[-1]
        ymax = self.fftsink.ref_level
        ymin = self.fftsink.ref_level - self.fftsink.y_per_div * self.fftsink.y_divs
        y_range = ymin, ymax
        self.plot.Draw (graphics, xAxis=x_range, yAxis=y_range, step=self.fftsink.y_per_div)        

    def set_peak_hold(self, enable):
        self.peak_hold = enable
        self.peak_vals = None

    def on_average(self, evt):
        # print "on_average"
        self.fftsink.set_average(evt.IsChecked())
        self.control_panel.update()

    def on_peak_hold(self, evt):
        # print "on_peak_hold"
        self.fftsink.set_peak_hold(evt.IsChecked())
        self.control_panel.update()

    def on_incr_ref_level(self, evt):
        # print "on_incr_ref_level"
        self.fftsink.set_ref_level(self.fftsink.ref_level
                                   + self.fftsink.y_per_div)

    def on_decr_ref_level(self, evt):
        # print "on_decr_ref_level"
        self.fftsink.set_ref_level(self.fftsink.ref_level
                                   - self.fftsink.y_per_div)

    def on_incr_y_per_div(self, evt):
        # print "on_incr_y_per_div"
        self.fftsink.set_y_per_div(next_up(self.fftsink.y_per_div, DIV_LEVELS))
        self.control_panel.update()

    def on_decr_y_per_div(self, evt):
        # print "on_decr_y_per_div"
        self.fftsink.set_y_per_div(next_down(self.fftsink.y_per_div, DIV_LEVELS))
        self.control_panel.update()

    def on_y_per_div(self, evt):
        # print "on_y_per_div"
        Id = evt.GetId()
        if Id == self.id_y_per_div_1:
            self.fftsink.set_y_per_div(1)
        elif Id == self.id_y_per_div_2:
            self.fftsink.set_y_per_div(2)
        elif Id == self.id_y_per_div_5:
            self.fftsink.set_y_per_div(5)
        elif Id == self.id_y_per_div_10:
            self.fftsink.set_y_per_div(10)
        elif Id == self.id_y_per_div_20:
            self.fftsink.set_y_per_div(20)
        self.control_panel.update()

    def on_right_click(self, event):
        menu = self.popup_menu
        for id, pred in self.checkmarks.items():
            item = menu.FindItemById(id)
            item.Check(pred())
        self.plot.PopupMenu(menu, event.GetPosition())

    def evt_motion(self, event):
        if not hasattr(self, "_points"):
            return # Got here before first window data update
            
        # Clip to plotted values
        (ux, uy) = self.plot.GetXY(event)      # Scaled position
        x_vals = numpy.array(self._points[:,0])
        if ux < x_vals[0] or ux > x_vals[-1]:
            tip = self.GetToolTip()
            if tip:
                tip.Enable(False)
            return

        # Get nearest X value (is there a better way)?
        ind = numpy.argmin(numpy.abs(x_vals-ux))
        x_val = x_vals[ind]
        db_val = self._points[ind, 1]
        text = (self._format+" %s dB=%3.3f") % (x_val, self._units, db_val)

        # Display the tooltip
        tip = wx.ToolTip(text)
        tip.Enable(True)
        tip.SetDelay(0)
        self.SetToolTip(tip)
        
    def build_popup_menu(self):
        self.id_incr_ref_level = wx.NewId()
        self.id_decr_ref_level = wx.NewId()
        self.id_incr_y_per_div = wx.NewId()
        self.id_decr_y_per_div = wx.NewId()
        self.id_y_per_div_1 = wx.NewId()
        self.id_y_per_div_2 = wx.NewId()
        self.id_y_per_div_5 = wx.NewId()
        self.id_y_per_div_10 = wx.NewId()
        self.id_y_per_div_20 = wx.NewId()
        self.id_average = wx.NewId()
        self.id_peak_hold = wx.NewId()
        
        self.plot.Bind(wx.EVT_MENU, self.on_average, id=self.id_average)
        self.plot.Bind(wx.EVT_MENU, self.on_peak_hold, id=self.id_peak_hold)
        self.plot.Bind(wx.EVT_MENU, self.on_incr_ref_level, id=self.id_incr_ref_level)
        self.plot.Bind(wx.EVT_MENU, self.on_decr_ref_level, id=self.id_decr_ref_level)
        self.plot.Bind(wx.EVT_MENU, self.on_incr_y_per_div, id=self.id_incr_y_per_div)
        self.plot.Bind(wx.EVT_MENU, self.on_decr_y_per_div, id=self.id_decr_y_per_div)
        self.plot.Bind(wx.EVT_MENU, self.on_y_per_div, id=self.id_y_per_div_1)
        self.plot.Bind(wx.EVT_MENU, self.on_y_per_div, id=self.id_y_per_div_2)
        self.plot.Bind(wx.EVT_MENU, self.on_y_per_div, id=self.id_y_per_div_5)
        self.plot.Bind(wx.EVT_MENU, self.on_y_per_div, id=self.id_y_per_div_10)
        self.plot.Bind(wx.EVT_MENU, self.on_y_per_div, id=self.id_y_per_div_20)
        
        # make a menu
        menu = wx.Menu()
        self.popup_menu = menu
        menu.AppendCheckItem(self.id_average, "Average")
        menu.AppendCheckItem(self.id_peak_hold, "Peak Hold")
        menu.Append(self.id_incr_ref_level, "Incr Ref Level")
        menu.Append(self.id_decr_ref_level, "Decr Ref Level")
        # menu.Append(self.id_incr_y_per_div, "Incr dB/div")
        # menu.Append(self.id_decr_y_per_div, "Decr dB/div")
        menu.AppendSeparator()
        # we'd use RadioItems for these, but they're not supported on Mac
        menu.AppendCheckItem(self.id_y_per_div_1, "1 dB/div")
        menu.AppendCheckItem(self.id_y_per_div_2, "2 dB/div")
        menu.AppendCheckItem(self.id_y_per_div_5, "5 dB/div")
        menu.AppendCheckItem(self.id_y_per_div_10, "10 dB/div")
        menu.AppendCheckItem(self.id_y_per_div_20, "20 dB/div")

        self.checkmarks = {
            self.id_average : lambda : self.fftsink.average,
            self.id_peak_hold : lambda : self.fftsink.peak_hold,
            self.id_y_per_div_1 : lambda : self.fftsink.y_per_div == 1,
            self.id_y_per_div_2 : lambda : self.fftsink.y_per_div == 2,
            self.id_y_per_div_5 : lambda : self.fftsink.y_per_div == 5,
            self.id_y_per_div_10 : lambda : self.fftsink.y_per_div == 10,
            self.id_y_per_div_20 : lambda : self.fftsink.y_per_div == 20,
            }


def next_up(v, seq):
    """
    Return the first item in seq that is > v.
    """
    for s in seq:
        if s > v:
            return s
    return v

def next_down(v, seq):
    """
    Return the last item in seq that is < v.
    """
    rseq = list(seq[:])
    rseq.reverse()

    for s in rseq:
        if s < v:
            return s
    return v


# ----------------------------------------------------------------
# Standalone test app
# ----------------------------------------------------------------

class test_app_block (stdgui2.std_top_block):
    def __init__(self, frame, panel, vbox, argv):
        stdgui2.std_top_block.__init__ (self, frame, panel, vbox, argv)

        fft_size = 256

        # build our flow graph
        input_rate = 20.48e3

        # Generate a complex sinusoid
        #src1 = gr.sig_source_c (input_rate, gr.GR_SIN_WAVE, 2e3, 1)
        src1 = gr.sig_source_c (input_rate, gr.GR_CONST_WAVE, 5.75e3, 1)

        # We add these throttle blocks so that this demo doesn't
        # suck down all the CPU available.  Normally you wouldn't use these.
        thr1 = gr.throttle(gr.sizeof_gr_complex, input_rate)

        sink1 = fft_sink_c (panel, title="Complex Data", fft_size=fft_size,
                            sample_rate=input_rate, baseband_freq=100e3,
                            ref_level=0, y_per_div=20, y_divs=10)
        vbox.Add (sink1.win, 1, wx.EXPAND)

        self.connect(src1, thr1, sink1)

        #src2 = gr.sig_source_f (input_rate, gr.GR_SIN_WAVE, 2e3, 1)
        src2 = gr.sig_source_f (input_rate, gr.GR_CONST_WAVE, 5.75e3, 1)
        thr2 = gr.throttle(gr.sizeof_float, input_rate)
        sink2 = fft_sink_f (panel, title="Real Data", fft_size=fft_size*2,
                            sample_rate=input_rate, baseband_freq=100e3,
                            ref_level=0, y_per_div=20, y_divs=10)
        vbox.Add (sink2.win, 1, wx.EXPAND)

        self.connect(src2, thr2, sink2)

def main ():
    app = stdgui2.stdapp (test_app_block, "FFT Sink Test App")
    app.MainLoop ()

if __name__ == '__main__':
    main ()