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- #!/usr/bin/python2.5
- #
- # Copyright 2014 Olivier Gillet.
- #
- # Author: Olivier Gillet (ol.gillet@gmail.com)
- #
- # Permission is hereby granted, free of charge, to any person obtaining a copy
- # of this software and associated documentation files (the "Software"), to deal
- # in the Software without restriction, including without limitation the rights
- # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- # copies of the Software, and to permit persons to whom the Software is
- # furnished to do so, subject to the following conditions:
- #
- # The above copyright notice and this permission notice shall be included in
- # all copies or substantial portions of the Software.
- #
- # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- # THE SOFTWARE.
- #
- # See http://creativecommons.org/licenses/MIT/ for more information.
- #
- # -----------------------------------------------------------------------------
- #
- # Lookup table definitions.
-
- import numpy
- import pylab
-
-
- def scale(x):
- xc = x - x.mean()
- abs_max = numpy.abs(xc).max()
- xc /= abs_max
- return xc
-
-
-
- def fshift(x, shift):
- s = x[:-1] + 0
- s = numpy.fft.rfft(s)
- s[1:] *= shift
- xh = numpy.fft.irfft(s)
- xh -= xh.mean()
- return numpy.array(list(xh) + [xh[0]])
-
-
-
- def make_quadrature(name, x, angle_1=0, angle_2=0.5):
- xc = fshift(x, numpy.exp(1j * angle_1 * numpy.pi))
- xh = fshift(x, numpy.exp(1j * angle_2 * numpy.pi))
- scale = max(numpy.abs(xc).max(), numpy.abs(xh).max())
- return [(name + '_i', xc / scale), (name + '_q', xh / scale)]
-
-
-
- SAMPLE_RATE = 96000
- WAVETABLE_SIZE = 1024
-
- t = numpy.arange(WAVETABLE_SIZE + 1) / float(WAVETABLE_SIZE) * 2 * numpy.pi
-
- sine = -numpy.sin(t)
- harmonics = -numpy.sin(t) - 0.5 * numpy.sin(2 * t) + 0.5 * numpy.sin(5 * t)
- buzzy = 0
- for i in xrange(7):
- buzzy += numpy.sin((1 + i) * t + 1.012 * i) * numpy.sin(1.123 * i)
-
- iq_waveforms = []
- iq_waveforms += make_quadrature('sine', sine)
- iq_waveforms += make_quadrature('harmonics', harmonics)
- iq_waveforms += make_quadrature('buzzy', buzzy)
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