def chirp_spectrum():
"""Plots the spectrum of a one-second one-octave linear chirp.
"""
signal = thinkdsp.Chirp(start=220, end=440)
wave = signal.make_wave(duration=1)
thinkplot.preplot(3, cols=3)
duration = 0.01
wave.segment(0, duration).plot()
thinkplot.config(ylim=[-1.05, 1.05])
thinkplot.subplot(2)
wave.segment(0.5, duration).plot()
thinkplot.config(yticklabels='invisible',
xlabel='Time (s)')
thinkplot.subplot(3)
wave.segment(0.9, duration).plot()
thinkplot.config(yticklabels='invisible')
thinkplot.save('chirp3')
spectrum = wave.make_spectrum()
spectrum.plot(high=700)
thinkplot.save('chirp1',
xlabel='Frequency (Hz)')
def chirp_spectrum():
"""Plots the spectrum of a one-second one-octave linear chirp.
"""
signal = thinkdsp.Chirp(start=220, end=440)
wave = signal.make_wave(duration=1)
spectrum = wave.make_spectrum()
spectrum.plot(high=660)
thinkplot.save('chirp1', xlabel='frequency (Hz)', ylabel='amplitude')
def get_chirp_wave_data(freq,
offset,
duration=0.1,
framerate=40000,
noise_ratio=0):
signal = thinkdsp.Chirp(start=freq * 0.5, end=1.5, amp=1.0)
wave = signal.make_wave(duration=duration, start=0, framerate=framerate)
if noise_ratio != 0:
wave.ys += numpy.random.standard_normal(wave.ys.shape) * noise_ratio
return wave.ys
def invert_spectrogram():
"""Tests Spectrogram.make_wave.
"""
signal = thinkdsp.Chirp(start=220, end=440)
wave = signal.make_wave(duration=1, framerate=11025)
spectrogram = wave.make_spectrogram(seg_length=512)
wave2 = spectrogram.make_wave()
for i, (y1, y2) in enumerate(zip(wave.ys, wave2.ys)):
if abs(y1 - y2) > 1e-14:
print(i, y1, y2)
def eye_of_sauron(start, end):
"""Plots the spectrum of a chirp.
start: initial frequency
end: final frequency
"""
signal = thinkdsp.Chirp(start=start, end=end)
wave = signal.make_wave(duration=0.5)
spectrum = wave.make_spectrum()
spectrum.plot(high=1200)
thinkplot.config(xlabel='frequency (Hz)', ylabel='amplitude')
def chirp_spectrogram():
"""Makes a spectrogram of a one-second one-octave linear chirp.
"""
signal = thinkdsp.Chirp(start=220, end=440)
wave = signal.make_wave(duration=1, framerate=11025)
spectrogram = wave.make_spectrogram(seg_length=512)
print('time res', spectrogram.time_res)
print('freq res', spectrogram.freq_res)
print('product', spectrogram.time_res * spectrogram.freq_res)
spectrogram.plot(high=32)
thinkplot.save('chirp2', xlabel='time (s)', ylabel='frequency (Hz)')
def main():
chirp_spectrogram()
chirp_spectrum()
return
violin_spectrogram()
return
invert_image()
return
invert_spectrogram()
return
overlapping_windows()
return
window_plot()
three_spectrums()
return
linear_chirp_evaluate(range(4))
signal = thinkdsp.Chirp(start=220, end=880)
wave1 = signal.make_wave(duration=2)
wave1.apodize()
signal = thinkdsp.ExpoChirp(start=220, end=880)
wave2 = signal.make_wave(duration=2)
wave2.apodize()
filename = 'chirp.wav'
wfile = thinkdsp.WavFileWriter(filename, wave1.framerate)
wfile.write(wave1)
wfile.write(wave2)
wfile.close
def testChirp(self):
signal = thinkdsp.Chirp(100, 200, 0.5)
result = signal.evaluate([1.001, 1.002, 1.005])
self.assertAlmostEqual(result[0], 0.5)
self.assertAlmostEqual(result[2], -0.49384417)
# In[1]: from __future__ import print_function, division get_ipython().magic(u'matplotlib inline') import thinkdsp import thinkplot import numpy as np from ipywidgets import interact, interactive, fixed import ipywidgets as widgets # In[2]: signal = thinkdsp.Chirp(start=220, end=880) wave1 = signal.make_wave(duration=2) wave1.make_audio() # In[3]: wave1.segment(start=0, duration=0.01).plot() # In[4]: wave1.segment(start=0.9, duration=0.01).plot() # In[5]: def evaluate(self, ts):
def testChirp(self):
signal = thinkdsp.Chirp(100, 200, 0.5)
result = signal.evaluate([0, 0.001, 0.002])
self.assertAlmostEqual(result[0], 0.5)
self.assertAlmostEqual(result[2], -0.29389263)
