#!/usr/bin/env python
#
# Copyright 2004 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 2, 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., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.
# 

from gnuradio import gr
from gnuradio import audio

def build_graph ():
    sampling_freq = 8e6

    fg = gr.flow_graph ()
    src0 = gr.sig_source_f ( sampling_freq, gr.GR_SIN_WAVE, 455e3, 40, 0 )
    src1 = gr.sig_source_f ( sampling_freq, gr.GR_SIN_WAVE, 1e3, 14, 0 )
    add = gr.add_const_ff (20)
    mixer = gr.multiply_ff ()
    dst = gr.file_sink (gr.sizeof_short, "dummy.dat")

    coeffs = \
       gr.firdes.band_pass (
          1.0,
          sampling_freq,
          75e3,
          2e6,
          50e3,
          gr.firdes.WIN_HAMMING)

    filter = gr.fir_filter_fsf (1, coeffs)

    fg.connect ( src0, (mixer, 0) )
    fg.connect ( add, (mixer, 1) )
    fg.connect ( src1, add )
    fg.connect ( mixer, filter )
    fg.connect ( filter, dst )

    return fg

if __name__ == '__main__':
    fg = build_graph ()
    fg.start ()
    raw_input ('Press Enter to quit: ')
    fg.stop ()