def test_bandpass(self):
"""Band pass filtering."""
# bandpass around the middle frequency
fn = self.dat.fs / 2
b, a = butter(4, [6 / fn, 8 / fn], btype='band')
ans = filtfilt(self.dat, b, a)
# check if the desired band is not damped
dat = spectrum(ans)
mask = dat.axes[0] == 7
self.assertTrue((dat.data[mask] > 6.5).all())
# check if the outer freqs are damped close to zero
mask = (dat.axes[0] <= 6) & (dat.axes[0] > 8)
self.assertTrue((dat.data[mask] < .5).all())
def test_spectrum(self):
"""Calculate the spectrum."""
dat = spectrum(self.dat)
# check that the amplitudes are almost correct
for idx, freq in enumerate(self.freqs):
for chan in range(dat.data.shape[1]):
self.assertAlmostEqual(dat.data[dat.axes[0] == freq, chan], self.amps[idx], delta=.15)
# check the amplitudes for the remaining freqs are almost zero
mask = (dat.axes[0] != self.freqs[0]) & (dat.axes[0] != self.freqs[1]) & (dat.axes[0] != self.freqs[2])
self.assertFalse((dat.data[mask] > .8).any())
# check that the max freq is < self.dat.fs / 2, and min freq > 0
self.assertGreater(min(dat.axes[0]), 0)
self.assertLess(max(dat.axes[0]), self.dat.fs / 2)
def test_spectrum_swapaxes(self):
"""spectrum must work with nonstandard timeaxis."""
dat = spectrum(swapaxes(self.dat, 0, 1), timeaxis=1)
dat = swapaxes(dat, 0, 1)
dat2 = spectrum(self.dat)
self.assertEqual(dat, dat2)
def test_spectrum_copy(self):
"""spectrum must not modify argument."""
cpy = self.dat.copy()
spectrum(self.dat)
self.assertEqual(cpy, self.dat)
def test_spectrum_has_no_fs(self):
"""A spectrum has no sampling freq."""
dat = spectrum(self.dat)
self.assertFalse(hasattr(dat, 'fs'))
