View source for Stereo FM transmitter using gnuradio

==Python code==

 #!/usr/bin/env python
 ##################################################
 # Gnuradio Python Flow Graph
 # Title: FM Stereo Transmitter
 # Author: Mathias Coinchon
 # Generated: Sat Jan  2 19:06:07 2010
 ##################################################
 
 from gnuradio import blks2
 from gnuradio import gr
 from gnuradio.eng_option import eng_option
 from gnuradio.gr import firdes
 from gnuradio.wxgui import fftsink2
 from gnuradio.wxgui import forms
 from grc_gnuradio import usrp as grc_usrp
 from grc_gnuradio import wxgui as grc_wxgui
 from optparse import OptionParser
 import wx
 
 class FM_stereo_tx(grc_wxgui.top_block_gui):
 
 	def __init__(self):
 		grc_wxgui.top_block_gui.__init__(self, title="FM Stereo Transmitter")
 
 		##################################################
 		# Variables
 		##################################################
 		self.st_gain = st_gain = 10
 		self.samp_rate = samp_rate = 32000
 		self.pilot_gain = pilot_gain = 80e-3
 		self.mpx_rate = mpx_rate = 160000
 		self.Mono_gain = Mono_gain = 0.3
 		self.FM_freq = FM_freq = 107900000
 
 		##################################################
 		# Controls
 		##################################################
 		_st_gain_sizer = wx.BoxSizer(wx.VERTICAL)
 		self._st_gain_text_box = forms.text_box(
 			parent=self.GetWin(),
 			sizer=_st_gain_sizer,
 			value=self.st_gain,
 			callback=self.set_st_gain,
 			label="Stereo gain",
 			converter=forms.float_converter(),
 			proportion=0,
 		)
 		self._st_gain_slider = forms.slider(
 			parent=self.GetWin(),
 			sizer=_st_gain_sizer,
 			value=self.st_gain,
 			callback=self.set_st_gain,
 			minimum=0,
 			maximum=100,
 			num_steps=100,
 			style=wx.SL_HORIZONTAL,
 			cast=float,
 			proportion=1,
 		)
 		self.Add(_st_gain_sizer)
 		_pilot_gain_sizer = wx.BoxSizer(wx.VERTICAL)
 		self._pilot_gain_text_box = forms.text_box(
 			parent=self.GetWin(),
 			sizer=_pilot_gain_sizer,
 			value=self.pilot_gain,
 			callback=self.set_pilot_gain,
 			label='pilot_gain',
 			converter=forms.float_converter(),
 			proportion=0,
 		)
 		self._pilot_gain_slider = forms.slider(
 			parent=self.GetWin(),
 			sizer=_pilot_gain_sizer,
 			value=self.pilot_gain,
 			callback=self.set_pilot_gain,
 			minimum=0,
 			maximum=1,
 			num_steps=100,
 			style=wx.SL_HORIZONTAL,
 			cast=float,
 			proportion=1,
 		)
 		self.Add(_pilot_gain_sizer)
 		_Mono_gain_sizer = wx.BoxSizer(wx.VERTICAL)
 		self._Mono_gain_text_box = forms.text_box(
 			parent=self.GetWin(),
 			sizer=_Mono_gain_sizer,
 			value=self.Mono_gain,
 			callback=self.set_Mono_gain,
 			label="Mono signal gain",
 			converter=forms.float_converter(),
 			proportion=0,
 		)
 		self._Mono_gain_slider = forms.slider(
 			parent=self.GetWin(),
 			sizer=_Mono_gain_sizer,
 			value=self.Mono_gain,
 			callback=self.set_Mono_gain,
 			minimum=0,
 			maximum=1,
 			num_steps=100,
 			style=wx.SL_HORIZONTAL,
 			cast=float,
 			proportion=1,
 		)
 		self.Add(_Mono_gain_sizer)
 		_FM_freq_sizer = wx.BoxSizer(wx.VERTICAL)
 		self._FM_freq_text_box = forms.text_box(
 			parent=self.GetWin(),
 			sizer=_FM_freq_sizer,
 			value=self.FM_freq,
 			callback=self.set_FM_freq,
 			label="FM Frequency",
 			converter=forms.float_converter(),
 			proportion=0,
 		)
 		self._FM_freq_slider = forms.slider(
 			parent=self.GetWin(),
 			sizer=_FM_freq_sizer,
 			value=self.FM_freq,
 			callback=self.set_FM_freq,
 			minimum=87500000,
 			maximum=108000000,
 			num_steps=205,
 			style=wx.SL_HORIZONTAL,
 			cast=float,
 			proportion=1,
 		)
 		self.Add(_FM_freq_sizer)
 
 		##################################################
 		# Blocks
 		##################################################
 		self.Audio_A_resampler = blks2.rational_resampler_fff(
 			interpolation=5,
 			decimation=1,
 			taps=None,
 			fractional_bw=None,
 		)
 		self.Audio_B_resampler = blks2.rational_resampler_fff(
 			interpolation=5,
 			decimation=1,
 			taps=None,
 			fractional_bw=None,
 		)
 		self.MPX_upsampler = blks2.rational_resampler_fff(
 			interpolation=4,
 			decimation=1,
 			taps=None,
 			fractional_bw=None,
 		)
 		self.Pilot = gr.sig_source_f(mpx_rate, gr.GR_SIN_WAVE, 19000, pilot_gain, 0)
 		self.band_pass_filter_0 = gr.fir_filter_fff(1, firdes.band_pass(
 			st_gain, mpx_rate, 23e3, 53e3, 2e3, firdes.WIN_HAMMING, 6.76))
 		self.blks2_fm_preemph_0 = blks2.fm_preemph(fs=mpx_rate, tau=50e-6)
 		self.gr_add_xx_0 = gr.add_vff(1)
 		self.gr_add_xx_1 = gr.add_vff(1)
 		self.gr_file_source_0 = gr.file_source(gr.sizeof_short*2, "/home/mc/FM_demo/stream_32k.fifo", True)
 		self.gr_frequency_modulator_fc_0 = gr.frequency_modulator_fc(0.98)
 		self.gr_multiply_const_vxx_0 = gr.multiply_const_vcc((32768, ))
 		self.gr_multiply_const_vxx_1 = gr.multiply_const_vff((0.00003, ))
 		self.gr_multiply_const_vxx_3 = gr.multiply_const_vff((0.00003, ))
 		self.gr_multiply_xx_1 = gr.multiply_vff(1)
 		self.gr_short_to_float_0 = gr.short_to_float()
 		self.gr_short_to_float_1 = gr.short_to_float()
 		self.gr_sub_xx_0 = gr.sub_ff(1)
 		self.gr_vector_to_streams_0 = gr.vector_to_streams(gr.sizeof_short*1, 2)
 		self.low_pass_filter_0 = gr.fir_filter_fff(1, firdes.low_pass(
 			Mono_gain, mpx_rate, 15e3, 2e3, firdes.WIN_HAMMING, 6.76))
 		self.st_38k_carrier = gr.sig_source_f(mpx_rate, gr.GR_SIN_WAVE, 38000, 30e-3, 0)
 		self.usrp_simple_sink_x_0 = grc_usrp.simple_sink_c(which=0, side="B")
 		self.usrp_simple_sink_x_0.set_interp_rate(200)
 		self.usrp_simple_sink_x_0.set_frequency(-FM_freq, verbose=True)
 		self.usrp_simple_sink_x_0.set_gain(0)
 		self.usrp_simple_sink_x_0.set_enable(True)
 		self.wxgui_fftsink2_0 = fftsink2.fft_sink_f(
 			self.GetWin(),
 			baseband_freq=0,
 			y_per_div=10,
 			y_divs=10,
 			ref_level=50,
 			sample_rate=mpx_rate,
 			fft_size=1024,
 			fft_rate=30,
 			average=False,
 			avg_alpha=None,
 			title="Baseband spectrum",
 			peak_hold=False,
 		)
 		self.Add(self.wxgui_fftsink2_0.win)
 
 		##################################################
 		# Connections
 		##################################################
 		self.connect((self.Audio_A_resampler, 0), (self.gr_add_xx_1, 0))
 		self.connect((self.Audio_B_resampler, 0), (self.gr_add_xx_1, 1))
 		self.connect((self.Audio_A_resampler, 0), (self.gr_sub_xx_0, 0))
 		self.connect((self.gr_multiply_xx_1, 0), (self.band_pass_filter_0, 0))
 		self.connect((self.st_38k_carrier, 0), (self.gr_multiply_xx_1, 1))
 		self.connect((self.low_pass_filter_0, 0), (self.gr_add_xx_0, 0))
 		self.connect((self.gr_add_xx_1, 0), (self.low_pass_filter_0, 0))
 		self.connect((self.gr_frequency_modulator_fc_0, 0), (self.gr_multiply_const_vxx_0, 0))
 		self.connect((self.MPX_upsampler, 0), (self.gr_frequency_modulator_fc_0, 0))
 		self.connect((self.blks2_fm_preemph_0, 0), (self.MPX_upsampler, 0))
 		self.connect((self.gr_add_xx_0, 0), (self.blks2_fm_preemph_0, 0))
 		self.connect((self.Pilot, 0), (self.gr_add_xx_0, 2))
 		self.connect((self.band_pass_filter_0, 0), (self.gr_add_xx_0, 1))
 		self.connect((self.gr_add_xx_0, 0), (self.wxgui_fftsink2_0, 0))
 		self.connect((self.gr_sub_xx_0, 0), (self.gr_multiply_xx_1, 0))
 		self.connect((self.Audio_B_resampler, 0), (self.gr_sub_xx_0, 1))
 		self.connect((self.gr_multiply_const_vxx_0, 0), (self.usrp_simple_sink_x_0, 0))
 		self.connect((self.gr_file_source_0, 0), (self.gr_vector_to_streams_0, 0))
 		self.connect((self.gr_short_to_float_1, 0), (self.gr_multiply_const_vxx_1, 0))
 		self.connect((self.gr_multiply_const_vxx_1, 0), (self.Audio_A_resampler, 0))
 		self.connect((self.gr_short_to_float_0, 0), (self.gr_multiply_const_vxx_3, 0))
 		self.connect((self.gr_multiply_const_vxx_3, 0), (self.Audio_B_resampler, 0))
 		self.connect((self.gr_vector_to_streams_0, 1), (self.gr_short_to_float_1, 0))
 		self.connect((self.gr_vector_to_streams_0, 0), (self.gr_short_to_float_0, 0))
 
 	def set_st_gain(self, st_gain):
 		self.st_gain = st_gain
 		self.band_pass_filter_0.set_taps(firdes.band_pass(self.st_gain, self.mpx_rate, 23e3, 53e3, 2e3, firdes.WIN_HAMMING, 6.76))
 		self._st_gain_slider.set_value(self.st_gain)
 		self._st_gain_text_box.set_value(self.st_gain)
 
 	def set_samp_rate(self, samp_rate):
 		self.samp_rate = samp_rate
 
 	def set_pilot_gain(self, pilot_gain):
 		self.pilot_gain = pilot_gain
 		self.Pilot.set_amplitude(self.pilot_gain)
 		self._pilot_gain_slider.set_value(self.pilot_gain)
 		self._pilot_gain_text_box.set_value(self.pilot_gain)
 
 	def set_mpx_rate(self, mpx_rate):
 		self.mpx_rate = mpx_rate
 		self.band_pass_filter_0.set_taps(firdes.band_pass(self.st_gain, self.mpx_rate, 23e3, 53e3, 2e3, firdes.WIN_HAMMING, 6.76))
 		self.low_pass_filter_0.set_taps(firdes.low_pass(self.Mono_gain, self.mpx_rate, 15e3, 2e3, firdes.WIN_HAMMING, 6.76))
 		self.Pilot.set_sampling_freq(self.mpx_rate)
 		self.st_38k_carrier.set_sampling_freq(self.mpx_rate)
 		self.wxgui_fftsink2_0.set_sample_rate(self.mpx_rate)
 
 	def set_Mono_gain(self, Mono_gain):
 		self.Mono_gain = Mono_gain
 		self.low_pass_filter_0.set_taps(firdes.low_pass(self.Mono_gain, self.mpx_rate, 15e3, 2e3, firdes.WIN_HAMMING, 6.76))
 		self._Mono_gain_slider.set_value(self.Mono_gain)
 		self._Mono_gain_text_box.set_value(self.Mono_gain)
 
 	def set_FM_freq(self, FM_freq):
 		self.FM_freq = FM_freq
 		self.usrp_simple_sink_x_0.set_frequency(-self.FM_freq)
 		self._FM_freq_slider.set_value(self.FM_freq)
 		self._FM_freq_text_box.set_value(self.FM_freq)
 
 if __name__ == '__main__':
 	parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
 	(options, args) = parser.parse_args()
 	tb = FM_stereo_tx()
 	tb.Run(True)