Coinchon at 09:08, 15 April 2013

2013-04-15T09:08:35Z

Coinchon at 20:32, 2 January 2010

2010-01-02T20:32:10Z

Coinchon at 18:15, 2 January 2010

2010-01-02T18:15:38Z

Coinchon: /* GRC Schema */

2010-01-02T18:13:35Z

GRC Schema

Coinchon at 18:12, 2 January 2010

2010-01-02T18:12:39Z

Coinchon: New page: ==Python code== #!/usr/bin/env python ################################################## # Gnuradio Python Flow Graph # Title: FM Stereo Transmitter # Author: Mathias Coinchon # G...

2010-01-02T18:12:02Z

New page: ==Python code== #!/usr/bin/env python ################################################## # Gnuradio Python Flow Graph # Title: FM Stereo Transmitter # Author: Mathias Coinchon # G...

New page

==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)

← Older revision		Revision as of 09:08, 15 April 2013
Line 24:		Line 24:

	==GRC Schema==		==GRC Schema==
		+
		+	'''ERROR: An error exists in this program, preemphasis block must be added on audio and not the whole signal, it is advised to use the other [[FM RDS Stereo transmitter using gnuradio]] (error on this one will be corrected in the future, orginal source has been lost)'''

	[[Image:FM transmitter stereo.png]]		[[Image:FM transmitter stereo.png]]

@@ Line 21: / Line 21: @@
 "-r32000" perform sample rate conversion to 32kHz.
+''Note: This transmitter could be used without USRP by feeding the multiplex stream to to a high samplerate soundcard connected to a hardware FM modulator. To be tested...''
 ==GRC Schema==

← Older revision		Revision as of 18:15, 2 January 2010
Line 1:		Line 1:
		+	Stereo FM transmitter using gnuradio.
		+
		+	Tools needed:
		+	*gnuradio 3.2
		+	*grc (gnuradio companion)
		+	*mpg123
		+	*USRP
		+
		+
		+	In this example we will show how to make a Stereo FM software transmitter. Input is from an mp3 stream for an Internet radio.
		+	Look at GRC schema or use directly python code below.
		+
		+	Input file is a unix FIFO file that means that we need to feed it externally from the shell using these commands:
		+
		+	Creation of the FIFO file (once):
		+	mkfifo stream_32k.fifo
		+
		+	Decoding of an mp3 Internet radio station stream, conversion and output of raw linear samples to the FIFO:
		+	mpg123 -r32000 -s http://maxxima.mine.nu:8000 >stream_32k.fifo
		+
		+	"-r32000" perform sample rate conversion to 32kHz.
		+
		+
		+
	==GRC Schema==		==GRC Schema==

← Older revision		Revision as of 18:13, 2 January 2010
Line 1:		Line 1:
−
−
	==GRC Schema==		==GRC Schema==

		+	[[Image:FM transmitter stereo.png]]

	==Python code==		==Python code==