def test_lowpassCheby2(self):
"""
Check magnitudes of basic lowpass cheby2
"""
df = 200 # Hz
b, a = lowpassCheby2(data=None, freq=50, df=df, maxorder=12, ba=True)
nyquist = 200 * 0.5
# calculate frequency response
w, h = sg.freqz(b, a, int(nyquist))
freq = w / np.pi * nyquist
h_db = 20 * np.log10(abs(h))
# be smaller than -96dB above lowpass frequency
self.assertTrue(h_db[freq > 50].max() < -96)
# be 0 (1dB ripple) before filter ramp
self.assertTrue(h_db[freq < 25].min() > -1)
def test_lowpassCheby2(self):
"""
Check magnitudes of basic lowpass cheby2
"""
df = 200 # Hz
b, a = lowpassCheby2(data=None, freq=50, df=df, maxorder=12, ba=True)
nyquist = 200 * 0.5
# calculate frequency response
w, h = sg.freqz(b, a, int(nyquist))
freq = w / np.pi * nyquist
h_db = 20 * np.log10(abs(h))
# be smaller than -96dB above lowpass frequency
self.assertTrue(h_db[freq > 50].max() < -96)
# be 0 (1dB ripple) before filter ramp
self.assertTrue(h_db[freq < 25].min() > -1)
def test_decimate(self):
"""
Tests the decimate method of the Trace object.
"""
# create test Trace
tr = Trace(data=np.arange(20))
tr_bkp = deepcopy(tr)
# some test that should fail and leave the original trace alone
self.assertRaises(ValueError, tr.decimate, 7, strict_length=True)
self.assertRaises(ValueError, tr.decimate, 9, strict_length=True)
self.assertRaises(ArithmeticError, tr.decimate, 18)
# some tests in place
tr.decimate(4, no_filter=True)
np.testing.assert_array_equal(tr.data, np.arange(0, 20, 4))
self.assertEqual(tr.stats.npts, 5)
self.assertEqual(tr.stats.sampling_rate, 0.25)
self.assertTrue("decimate" in tr.stats.processing[0])
self.assertTrue("factor=4" in tr.stats.processing[0])
tr = tr_bkp.copy()
tr.decimate(10, no_filter=True)
np.testing.assert_array_equal(tr.data, np.arange(0, 20, 10))
self.assertEqual(tr.stats.npts, 2)
self.assertEqual(tr.stats.sampling_rate, 0.1)
self.assertTrue("decimate" in tr.stats.processing[0])
self.assertTrue("factor=10" in tr.stats.processing[0])
# some tests with automatic prefiltering
tr = tr_bkp.copy()
tr2 = tr_bkp.copy()
tr.decimate(4)
df = tr2.stats.sampling_rate
tr2.data, fp = lowpassCheby2(data=tr2.data,
freq=df * 0.5 / 4.0,
df=df,
maxorder=12,
ba=False,
freq_passband=True)
# check that iteratively determined pass band frequency is correct
self.assertAlmostEqual(0.0811378285461, fp, places=7)
tr2.decimate(4, no_filter=True)
np.testing.assert_array_equal(tr.data, tr2.data)
def test_decimate(self):
"""
Tests the decimate method of the Trace object.
"""
# create test Trace
tr = Trace(data=np.arange(20))
tr_bkp = deepcopy(tr)
# some test that should fail and leave the original trace alone
self.assertRaises(ValueError, tr.decimate, 7, strict_length=True)
self.assertRaises(ValueError, tr.decimate, 9, strict_length=True)
self.assertRaises(ArithmeticError, tr.decimate, 18)
# some tests in place
tr.decimate(4, no_filter=True)
np.testing.assert_array_equal(tr.data, np.arange(0, 20, 4))
self.assertEqual(tr.stats.npts, 5)
self.assertEqual(tr.stats.sampling_rate, 0.25)
self.assertTrue("decimate" in tr.stats.processing[0])
self.assertTrue("factor=4" in tr.stats.processing[0])
tr = tr_bkp.copy()
tr.decimate(10, no_filter=True)
np.testing.assert_array_equal(tr.data, np.arange(0, 20, 10))
self.assertEqual(tr.stats.npts, 2)
self.assertEqual(tr.stats.sampling_rate, 0.1)
self.assertTrue("decimate" in tr.stats.processing[0])
self.assertTrue("factor=10" in tr.stats.processing[0])
# some tests with automatic prefiltering
tr = tr_bkp.copy()
tr2 = tr_bkp.copy()
tr.decimate(4)
df = tr2.stats.sampling_rate
tr2.data, fp = lowpassCheby2(data=tr2.data, freq=df * 0.5 / 4.0,
df=df, maxorder=12, ba=False,
freq_passband=True)
# check that iteratively determined pass band frequency is correct
self.assertAlmostEqual(0.0811378285461, fp, places=7)
tr2.decimate(4, no_filter=True)
np.testing.assert_array_equal(tr.data, tr2.data)