def test_linear():
# Should detect *one* rising zero crossing
# Specify `AC_coupled` = False to prevent computation of DC offset,
# which is only a well-defined operation when there are two or more
# zero crossings of the same type.
zc = ZeroCrossing(np.array([-1, 0, 1]), 1, auto=False)
tools.assert_equal(zc._getRisingZeroCrossingIndices(), np.array([0]))
tools.assert_equal(zc._getRisingZeroCrossingTimesLerp(), np.array([1]))
def test_constant():
# Should detect *no* zero crossings with a constant array
# Specify `AC_coupled` = False to prevent computation of DC offset,
# which is only a well-defined operation when there are two or more
# zero crossings of the same type.
zc = ZeroCrossing(np.array([1, 1]), 1, auto=False)
tools.assert_equal(len(zc._getRisingZeroCrossingIndices()), 0)
tools.assert_equal(len(zc._getRisingZeroCrossingTimesLerp()), 0)
def test__getRisingZeroCrossingTimesLerp():
# Create signal with well-known zero crossings
f = 0.125
t = 0.5 + np.linspace(0, 100, 101)
y = np.cos(2 * np.pi * f * t)
Fs = 1. / np.mean(np.diff(t))
# Construct zero crossing object
zc = ZeroCrossing(y, Fs, t0=t[0])
# Test identification of *rising* zero crossings
# via linear interpolation
xtimes_rising_exact = np.arange(6, t[-1], int(1. / f))
xtimes_rising_calc = zc._getRisingZeroCrossingTimesLerp()
np.testing.assert_allclose(xtimes_rising_exact, xtimes_rising_calc)
# Test identification of *falling* zero crossings
# via linear interpolation
xtimes_falling_exact = np.arange(2, t[-1], int(1. / f))
xtimes_falling_calc = zc._getRisingZeroCrossingTimesLerp(invert=True)
np.testing.assert_allclose(xtimes_falling_exact, xtimes_falling_calc)
