#!/usr/bin/env python

#

# Copyright 2006 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, gr_unittest

from math import pi, cos

class test_goertzel(gr_unittest.TestCase):

    def setUp(self):

        self.fg = gr.flow_graph()

    def tearDown(self):

        self.fg = None

    def make_tone_data(self, rate, freq):

        return [cos(2*pi*x*freq/rate) for x in range(rate)]

    def transform(self, src_data, rate, freq):

        src = gr.vector_source_f(src_data, False)

        dft = gr.goertzel_fc(rate, rate, freq)

        dst = gr.vector_sink_c()

        self.fg.connect(src, dft, dst)

        self.fg.run()

        return dst.data()        

    def test_001(self): # Measure single tone magnitude

        rate = 8000

        freq = 100

        bin = freq

        src_data = self.make_tone_data(rate, freq)

        expected_result = 0.5

        actual_result = abs(self.transform(src_data, rate, bin)[0])

        self.assertAlmostEqual(expected_result, actual_result, places=5)

    def test_002(self): # Measure off frequency magnitude

        rate = 8000

        freq = 100

        bin = freq/2

        src_data = self.make_tone_data(rate, freq)

        expected_result = 0.0

        actual_result = abs(self.transform(src_data, rate, bin)[0])

        self.assertAlmostEqual(expected_result, actual_result, places=5)

if __name__ == '__main__':

    gr_unittest.main()