def test_THD_lin(self):
far = adsp.Farina(20, _fs_)
meas = self.lin_sys(far.probe)
far.process_measurement(meas)
thd = far.getTHD()
self.assertTrue(thd < 0.1, 'Incorrect THD for linear system!')
def test_inverse_probe_imp(self):
far = adsp.Farina(10, _fs_)
delta = signal.convolve(far.probe, far.inv_probe)
delta_sort = np.sort(np.abs(delta))
ratio = delta_sort[-1] / delta_sort[-2]
self.assertTrue(
ratio > 5, 'Probe and inverse probe does not convolve to a delta!')
def test_inverse_probe_freq(self):
far = adsp.Farina(10, _fs_)
delta = signal.convolve(far.probe, far.inv_probe)
freqs = np.fft.rfftfreq(len(delta), 1.0 / _fs_)
start = np.argwhere(freqs > 100)[0][0]
end = np.argwhere(freqs < 16000)[-1][0]
delta_fft = 20 * \
np.log10(adsp.normalize(np.abs(np.fft.rfft(delta))))[start:end]
rangeDB = np.max(delta_fft) - np.min(delta_fft)
self.assertTrue(
rangeDB < 2.0,
'Inverse probe does not have correct frequency response!')
def test_freq_response_nonlin(self):
far = adsp.Farina(20, _fs_)
meas = self.nonlin_sys(far.probe)
far.process_measurement(meas)
freqs = np.fft.rfftfreq(self.N, 1.0 / _fs_)
start = np.argwhere(freqs > 100)[0][0]
end = np.argwhere(freqs < 16000)[-1][0]
test_fft = 20 * \
np.log10(adsp.normalize(np.abs(np.fft.rfft(self.test_filt))))[
start:end]
far_fft = 20 * \
np.log10(adsp.normalize(np.abs(np.fft.rfft(far.get_IR()[:self.N]))))[
start:end]
error = np.max(np.abs(test_fft - far_fft))
self.assertTrue(error < 10,
'Incorrect frequency response for nonlinear system!')
def test_THD_nonlin(self):
# get reference THD from sine wave test
N = _fs_ * 2
freq = 1000
sine = np.sin(2 * np.pi * np.arange(N) * freq / _fs_)
y = self.nonlin_sys(sine)
V_rms = np.zeros(9)
for n in range(1, 10):
low_freq = freq * n - 30
b_hpf, a_hpf = signal.butter(4,
low_freq,
btype='highpass',
analog=False,
fs=_fs_)
high_freq = freq * n + 30
b_lpf, a_lpf = signal.butter(4,
high_freq,
btype='lowpass',
analog=False,
fs=_fs_)
harmonic = signal.lfilter(b_hpf, a_hpf,
(signal.lfilter(b_lpf, a_lpf, y)))
V_rms[n - 1] = np.sqrt(np.mean(harmonic**2))
sine_thd = np.sqrt(np.sum(V_rms[1:]**2)) / V_rms[0]
# get measured THD from Farina
far = adsp.Farina(20, _fs_)
meas = self.nonlin_sys(far.probe)
far.process_measurement(meas)
far_thd = far.getTHD()
error = np.abs(far_thd - sine_thd)
self.assertTrue(error < 0.1,
f'Incorrect THD! Sine: {sine_thd}, Far: {far_thd}')