[scitools] push by oyvind.r...@gmail.com - Added functions for playing square and triangle waves and their Fourie... on 2014-02-18 09:20 GMT

[scit...@googlecode.com]

Revision: 2db3cb5076aa
Branch: default
Author: oyvind.ryan
Date: Tue Feb 18 09:18:48 2014 UTC
Log: Added functions for playing square and triangle waves and their
Fourier series
http://code.google.com/p/scitools/source/detail?r=2db3cb5076aa

Modified:
/lib/scitools/sound.py

=======================================
--- /lib/scitools/sound.py Mon Feb 17 10:23:27 2014 UTC
+++ /lib/scitools/sound.py Tue Feb 18 09:18:48 2014 UTC
@@ -85,8 +85,8 @@
"""
m, n = numpy.shape(data)
data = data.astype(float)
- data = data+c*(2**15-1)*(2*numpy.random.rand(m,n))
- data = (2**15-1)*data/abs(data).max()
+ data = data+c*max_amplitude*(2*numpy.random.rand(m,n))
+ data = max_amplitude*data/abs(data).max()
data = data.astype(numpy.int16)
play(data, sample_rate)

@@ -111,7 +111,52 @@
data=data.reshape((len(data),1))
return data

+def play_square(T, length):
+ sample_rate = 44100
+ samplesperperiod = sample_rate*T
+ oneperiod = numpy.hstack([numpy.ones((1, samplesperperiod/2)),
-numpy.ones((1, samplesperperiod/2))])
+ oneperiod = max_amplitude*numpy.asarray(oneperiod)
+ data = numpy.tile(oneperiod,(1,length/T))
+ data = data.astype(numpy.int16)
+ m, n = numpy.shape(data)
+ data = data.reshape(n, 1)
+ play(data, sample_rate)

+def play_square_fourier(T, length, N):
+ sample_rate = 44100
+ t = numpy.linspace(0, length, sample_rate*length)
+ data = numpy.zeros(t.size)
+ for n in range(1,N+1,2):
+ data = data + numpy.sin(2*numpy.pi*n*t/T)/n
+ data = data*4/numpy.pi
+ data = max_amplitude*data/max(abs(data))
+ data = data.astype(numpy.int16)
+ data = data.reshape(len(data), 1)
+ play(data, sample_rate)
+
+def play_triangle(T, length):
+ sample_rate = 44100
+ samplesperperiod = sample_rate*T
+ oneperiod = numpy.hstack([numpy.linspace(-1, 1, samplesperperiod/2),
numpy.linspace(1, -1, samplesperperiod/2)])
+ oneperiod = max_amplitude*numpy.asarray(oneperiod)
+ data = numpy.tile(oneperiod, (1, length/T))
+ data = data.astype(numpy.int16)
+ m, n = numpy.shape(data)
+ data = data.reshape(n, 1)
+ play(data, sample_rate)
+
+def play_triangle_fourier(T, length, N):
+ sample_rate = 44100
+ t = numpy.linspace(0, length, sample_rate*length)
+ data = numpy.zeros(t.size)
+ for n in range(1,N+1,2):
+ data = data - numpy.cos(2*numpy.pi*n*t/T)/n**2
+ data = data*8/(numpy.pi**2)
+ data = max_amplitude*data/max(abs(data))
+ data = data.astype(numpy.int16)
+ data = data.reshape(len(data), 1)
+ play(data,sample_rate)
+
def _test1():
filename = 'tmp.wav'

@@ -320,3 +365,7 @@
play_with_echo(song,44100, 0.6, 0.5)
play_reverse(song, 44100)
play_with_noise(song, 44100, 0.7)
+ play_square(1/440.0, 3)
+ play_square_fourier(1/440.0, 3, 9)
+ play_triangle(1/440.0, 3)
+ play_triangle_fourier(1/440.0, 3, 3)