def freqz(sosmat, nsamples=44100, sample_rate=44100, plot=True):
"""Plots Frequency response of sosmat."""
from pylab import np, plt, fft, fftfreq
x = np.zeros(nsamples)
x[int(nsamples/2)] = 0.999
y, states = sosfilter_double_c(x, sosmat)
Y = fft(y)
f = fftfreq(len(x), 1.0/sample_rate)
if plot:
plt.grid(True)
plt.axis([0, sample_rate / 2, -100, 5])
L = 20*np.log10(np.abs(Y[:int(len(x)/2)]) + 1e-17)
plt.semilogx(f[:int(len(x)/2)], L, lw=0.5)
plt.hold(True)
plt.title(u'freqz sos filter')
plt.xlabel('Frequency / Hz')
plt.ylabel(u'Damping /dB(FS)')
plt.xlim((10, sample_rate/2))
plt.hold(False)
return x, y, f, Y
def freqz(sosmat, nsamples=44100, sample_rate=44100, plot=True):
"""Plots Frequency response of sosmat."""
from pylab import np, plt, fft, fftfreq
x = np.zeros(nsamples)
x[nsamples/2] = 0.999
y, states = sosfilter_double_c(x, sosmat)
Y = fft(y)
f = fftfreq(len(x), 1.0/sample_rate)
if plot:
plt.grid(True)
plt.axis([0, sample_rate / 2, -100, 5])
L = 20*np.log10(np.abs(Y[:len(x)/2]) + 1e-17)
plt.semilogx(f[:len(x)/2], L, lw=0.5)
plt.hold(True)
plt.title('freqz sos filter')
plt.xlabel('Frequency / Hz')
plt.ylabel('Damping /dB(FS)')
plt.xlim((10, sample_rate/2))
plt.hold(False)
return x, y, f, Y
def plotfun(x, y):
ax.semilogx(x, 20*np.log10(np.abs(y)**2))
plt.hold(True)
def plotfun(x, y):
ax.semilogx(x, 20 * np.log10(np.abs(y)**2))
plt.hold(True)
def freqz(ofb, length_sec=6, ffilt=False, plot=True):
"""Computes the IR and FRF of a digital filter.
Parameters
----------
ofb : FractionalOctaveFilterbank object
length_sec : scalar
Length of the impulse response test signal.
ffilt : bool
Backard forward filtering. Effectiv order is doubled then.
plot : bool
Create Plots or not.
Returns
-------
x : ndarray
Impulse test signal.
y : ndarray
Impules responses signal of the filters.
f : ndarray
Frequency vector for the FRF.
Y : Frequency response (FRF) of the summed filters.
"""
from pylab import np, plt, fft, fftfreq
x = np.zeros(length_sec*ofb.sample_rate)
x[length_sec*ofb.sample_rate/2] = 0.9999
if not ffilt:
y, states = ofb.filter_mimo_c(x)
y = y[:, :, 0]
else:
y, states = ofb.filter(x, ffilt=ffilt)
s = np.zeros(len(x))
for i in range(y.shape[1]):
s += y[:, i]
X = fft(y[:, i]) # sampled frequency response
f = fftfreq(len(x), 1.0/ofb.sample_rate)
if plot:
fig = plt.figure('freqz filter bank')
plt.grid(True)
plt.axis([0, ofb.sample_rate / 2, -100, 5])
L = 20*np.log10(np.abs(X[:len(x)/2]) + 1e-17)
plt.semilogx(f[:len(x)/2], L, lw=0.5)
plt.hold(True)
Y = fft(s)
if plot:
plt.title(u'freqz() Filter Bank')
plt.xlabel('Frequency / Hz')
plt.ylabel(u'Damping /dB(FS)')
plt.xlim((10, ofb.sample_rate/2))
plt.hold(False)
plt.figure('sum')
L = 20*np.log10(np.abs(Y[:len(x)/2]) + 1e-17)
plt.semilogx(f[:len(x)/2], L, lw=0.5)
level_input = 10*np.log10(np.sum(x**2))
level_output = 10*np.log10(np.sum(s**2))
plt.axis([5, ofb.sample_rate/1.8, -50, 5])
plt.grid(True)
plt.title('Sum of filter bands')
plt.xlabel('Frequency / Hz')
plt.ylabel(u'Damping /dB(FS)')
print('sum level', level_output, level_input)
return x, y, f, Y
def freqz(ofb, length_sec=6, ffilt=False, plot=True):
"""Computes the IR and FRF of a digital filter.
Parameters
----------
ofb : FractionalOctaveFilterbank object
length_sec : scalar
Length of the impulse response test signal.
ffilt : bool
Backard forward filtering. Effectiv order is doubled then.
plot : bool
Create Plots or not.
Returns
-------
x : ndarray
Impulse test signal.
y : ndarray
Impules responses signal of the filters.
f : ndarray
Frequency vector for the FRF.
Y : Frequency response (FRF) of the summed filters.
"""
from pylab import np, plt, fft, fftfreq
x = np.zeros(length_sec*ofb.sample_rate)
x[length_sec*ofb.sample_rate/2] = 0.9999
if not ffilt:
y, states = ofb.filter_mimo_c(x)
y = y[:, :, 0]
else:
y, states = ofb.filter(x, ffilt=ffilt)
s = np.zeros(len(x))
for i in range(y.shape[1]):
s += y[:, i]
X = fft(y[:, i]) # sampled frequency response
f = fftfreq(len(x), 1.0/ofb.sample_rate)
if plot:
fig = plt.figure('freqz filter bank')
plt.grid(True)
plt.axis([0, ofb.sample_rate / 2, -100, 5])
L = 20*np.log10(np.abs(X[:len(x)/2]) + 1e-17)
plt.semilogx(f[:len(x)/2], L, lw=0.5)
plt.hold(True)
Y = fft(s)
if plot:
plt.title('freqz() Filter Bank')
plt.xlabel('Frequency / Hz')
plt.ylabel('Damping /dB(FS)')
plt.xlim((10, ofb.sample_rate/2))
plt.hold(False)
plt.figure('sum')
L = 20*np.log10(np.abs(Y[:len(x)/2]) + 1e-17)
plt.semilogx(f[:len(x)/2], L, lw=0.5)
level_input = 10*np.log10(np.sum(x**2))
level_output = 10*np.log10(np.sum(s**2))
plt.axis([5, ofb.sample_rate/1.8, -50, 5])
plt.grid(True)
plt.title('Sum of filter bands')
plt.xlabel('Frequency / Hz')
plt.ylabel('Damping /dB(FS)')
print('sum level', level_output, level_input)
return x, y, f, Y
