fftsink.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

#!/usr/bin/env python
#
# Copyright 2003,2004,2005,2006,2007 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 3, 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 GNU Radio; see the file COPYING.  If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
# 

from gnuradio import gr, gru, window
from gnuradio.wxgui import stdgui
import wx
import gnuradio.wxgui.plot as plot
import numpy
import threading
import math    

default_fftsink_size = (640,240)
default_fft_rate = gr.prefs().get_long('wxgui', 'fft_rate', 15)

class fft_sink_base(object):
    def __init__(self, input_is_real=False, baseband_freq=0, y_per_div=10, ref_level=50,
                 sample_rate=1, fft_size=512,
                 fft_rate=default_fft_rate,
                 average=False, avg_alpha=None, title='', peak_hold=False):

        # initialize common attributes
        self.baseband_freq = baseband_freq
        self.y_divs = 8
        self.y_per_div=y_per_div
        self.ref_level = ref_level
        self.sample_rate = sample_rate
        self.fft_size = fft_size
        self.fft_rate = fft_rate
        self.average = average
        if avg_alpha is None:
            self.avg_alpha = 2.0 / fft_rate
        else:
            self.avg_alpha = avg_alpha
        self.title = title
        self.peak_hold = peak_hold
        self.input_is_real = input_is_real
        self.msgq = gr.msg_queue(2)         # queue that holds a maximum of 2 messages

    def set_y_per_div(self, y_per_div):
        self.y_per_div = y_per_div

    def set_ref_level(self, ref_level):
        self.ref_level = ref_level

    def set_average(self, average):
        self.average = average
        if average:
            self.avg.set_taps(self.avg_alpha)
            self.set_peak_hold(False)
        else:
            self.avg.set_taps(1.0)

    def set_peak_hold(self, enable):
        self.peak_hold = enable
        if enable:
            self.set_average(False)
        self.win.set_peak_hold(enable)

    def set_avg_alpha(self, avg_alpha):
        self.avg_alpha = avg_alpha

    def set_baseband_freq(self, baseband_freq):
        self.baseband_freq = baseband_freq

    def set_sample_rate(self, sample_rate):
        self.sample_rate = sample_rate
        self._set_n()

    def _set_n(self):
        self.one_in_n.set_n(max(1, int(self.sample_rate/self.fft_size/self.fft_rate)))
        

class fft_sink_f(gr.hier_block, fft_sink_base):
    def __init__(self, fg, parent, baseband_freq=0,
                 y_per_div=10, ref_level=50, sample_rate=1, fft_size=512,
                 fft_rate=default_fft_rate, average=False, avg_alpha=None,
                 title='', size=default_fftsink_size, peak_hold=False):

        fft_sink_base.__init__(self, input_is_real=True, baseband_freq=baseband_freq,
                               y_per_div=y_per_div, ref_level=ref_level,
                               sample_rate=sample_rate, fft_size=fft_size,
                               fft_rate=fft_rate,
                               average=average, avg_alpha=avg_alpha, title=title,
                               peak_hold=peak_hold)
                               
        s2p = gr.stream_to_vector(gr.sizeof_float, self.fft_size)
        self.one_in_n = gr.keep_one_in_n(gr.sizeof_float * self.fft_size,
                                         max(1, int(self.sample_rate/self.fft_size/self.fft_rate)))

        mywindow = window.blackmanharris(self.fft_size)
        fft = gr.fft_vfc(self.fft_size, True, mywindow)
        power = 0
        for tap in mywindow:
            power += tap*tap
            
        c2mag = gr.complex_to_mag(self.fft_size)
        self.avg = gr.single_pole_iir_filter_ff(1.0, self.fft_size)

        # FIXME  We need to add 3dB to all bins but the DC bin
        log = gr.nlog10_ff(20, self.fft_size,
                           -20*math.log10(self.fft_size)-10*math.log10(power/self.fft_size))
        sink = gr.message_sink(gr.sizeof_float * self.fft_size, self.msgq, True)

        fg.connect (s2p, self.one_in_n, fft, c2mag, self.avg, log, sink)
        gr.hier_block.__init__(self, fg, s2p, sink)

        self.win = fft_window(self, parent, size=size)
        self.set_average(self.average)


class fft_sink_c(gr.hier_block, fft_sink_base):
    def __init__(self, fg, parent, baseband_freq=0,
                 y_per_div=10, ref_level=50, sample_rate=1, fft_size=512,
                 fft_rate=default_fft_rate, average=False, avg_alpha=None,
                 title='', size=default_fftsink_size, peak_hold=False):

        fft_sink_base.__init__(self, input_is_real=False, baseband_freq=baseband_freq,
                               y_per_div=y_per_div, ref_level=ref_level,
                               sample_rate=sample_rate, fft_size=fft_size,
                               fft_rate=fft_rate,
                               average=average, avg_alpha=avg_alpha, title=title,
                               peak_hold=peak_hold)

        s2p = gr.stream_to_vector(gr.sizeof_gr_complex, self.fft_size)
        self.one_in_n = gr.keep_one_in_n(gr.sizeof_gr_complex * self.fft_size,
                                         max(1, int(self.sample_rate/self.fft_size/self.fft_rate)))
        mywindow = window.blackmanharris(self.fft_size)
        power = 0
        for tap in mywindow:
            power += tap*tap
            
        fft = gr.fft_vcc(self.fft_size, True, mywindow)
        c2mag = gr.complex_to_mag(fft_size)
        self.avg = gr.single_pole_iir_filter_ff(1.0, fft_size)
        log = gr.nlog10_ff(20, self.fft_size,
                           -20*math.log10(self.fft_size)-10*math.log10(power/self.fft_size))
        sink = gr.message_sink(gr.sizeof_float * fft_size, self.msgq, True)

        fg.connect(s2p, self.one_in_n, fft, c2mag, self.avg, log, sink)
        gr.hier_block.__init__(self, fg, s2p, sink)

        self.win = fft_window(self, parent, size=size)
        self.set_average(self.average)


# ------------------------------------------------------------------------

myDATA_EVENT = wx.NewEventType()
EVT_DATA_EVENT = wx.PyEventBinder (myDATA_EVENT, 0)


class DataEvent(wx.PyEvent):
    def __init__(self, data):
        wx.PyEvent.__init__(self)
        self.SetEventType (myDATA_EVENT)
        self.data = data

    def Clone (self): 
        self.__class__ (self.GetId())


class input_watcher (threading.Thread):
    def __init__ (self, msgq, fft_size, event_receiver, **kwds):
        threading.Thread.__init__ (self, **kwds)
        self.setDaemon (1)
        self.msgq = msgq
        self.fft_size = fft_size
        self.event_receiver = event_receiver
        self.keep_running = True
        self.start ()

    def run (self):
        while (self.keep_running):
            msg = self.msgq.delete_head()  # blocking read of message queue
            itemsize = int(msg.arg1())
            nitems = int(msg.arg2())

            s = msg.to_string()            # get the body of the msg as a string

            # There may be more than one FFT frame in the message.
            # If so, we take only the last one
            if nitems > 1:
                start = itemsize * (nitems - 1)
                s = s[start:start+itemsize]

            complex_data = numpy.fromstring (s, numpy.float32)
            de = DataEvent (complex_data)
            wx.PostEvent (self.event_receiver, de)
            del de
    

class fft_window (plot.PlotCanvas):
    def __init__ (self, fftsink, parent, id = -1,
                  pos = wx.DefaultPosition, size = wx.DefaultSize,
                  style = wx.DEFAULT_FRAME_STYLE, name = ""):
        plot.PlotCanvas.__init__ (self, parent, id, pos, size, style, name)

        self.y_range = None
        self.fftsink = fftsink
        self.peak_hold = False
        self.peak_vals = None

        self.SetEnableGrid (True)
        # self.SetEnableZoom (True)
        # self.SetBackgroundColour ('black')
        
        self.build_popup_menu()
        
        EVT_DATA_EVENT (self, self.set_data)
        wx.EVT_CLOSE (self, self.on_close_window)
        self.Bind(wx.EVT_RIGHT_UP, self.on_right_click)

        self.input_watcher = input_watcher(fftsink.msgq, fftsink.fft_size, self)


    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: