#!/usr/bin/env python
#
# Copyright 2004,2005,2007 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.
#
#This program is designed to generate sine waves and demonstrate the filter function for capture in files.

from gnuradio import gr, optfir
from gnuradio import audio
from gnuradio.eng_option import eng_option
from optparse import OptionParser

class my_top_block(gr.top_block):

    def __init__(self):
        gr.top_block.__init__(self)

        parser = OptionParser(option_class=eng_option)
        parser.add_option("-O", "--audio-output", type="string", default="",
                          help="pcm output device name.  E.g., hw:0,0 or /dev/dsp")
        parser.add_option("-r", "--sample-rate", type="eng_float", default=48000,
                          help="set sample rate to RATE (48000)")
	parser.add_option("-a", "--ampl", type="eng_float", default=.1,
                          help="set amplitude (0.1)")
        (options, args) = parser.parse_args ()
        if len(args) != 0:
            parser.print_help()
            raise SystemExit, 1

        sample_rate = int(options.sample_rate)
        ampl = options.ampl

	summer_sink = gr.file_sink(gr.sizeof_gr_complex, "sum_c.dat")
	filter_sink = gr.file_sink(gr.sizeof_gr_complex, "filter.dat")
	

        src0 = gr.sig_source_c (sample_rate, gr.GR_SIN_WAVE, 1000, ampl)
        src1 = gr.sig_source_c (sample_rate, gr.GR_SQR_WAVE, 2000, ampl)

	summer = gr.add_cc()

	#create the channel filter coefficients
	chan_taps = optfir.low_pass(
		1.0,	#Filter gain
		48000,	#Sample Rate
		1500,	#one sided modulation BW (edge of passband)
		1800,   #one sided channel BW (edge of stopband)
		0.1,	#Passband ripple
		60)	#Stopband Attenuation

	print "Channel filter taps:", len(chan_taps)

	#creates the channel filter with the coef found above
	chan = gr.freq_xlating_fir_filter_ccf(
		1,	#Decimation rate
		chan_taps,  #coefficients
		0,	#Offset frequency - could be used to shift 
		48e3)  #incoming sample rate

	summer_sink = gr.file_sink(gr.sizeof_gr_complex, "sum_c.dat")
	filter_sink = gr.file_sink(gr.sizeof_gr_complex, "filter.dat")
	


	#creates a file for the output of the channel filter
	#chan_sink = gr.file_sink(gr.sizeof_gr_complex,"chan.dat")
	#self.connect(chan,chan_sink)

	ctof =gr.complex_to_float()
        dst = audio.sink (sample_rate, options.audio_output)

        self.connect (src0, (summer, 0))
        self.connect (src1, (summer, 1))
	self.connect (summer, chan, ctof, dst)
	self.connect (chan, filter_sink)
	self.connect (summer, summer_sink)


if __name__ == '__main__':
    try:
        my_top_block().run()
    except KeyboardInterrupt:
        pass