def plot_group_delay(self, a, b):
w, gd = signal.group_delay((b, a))
plt.plot(w, numpy.round(gd, 5))
plt.ylabel('Retardo de grupo [muestras]')
plt.xlabel('Frecuencia [rad/muestra]')
plt.title('Retardo de grupo')
plt.show()
def zplane(self, a, b):
# Fix axes
ax = plt.gca()
ax.spines['left'].set_position('zero')
ax.spines['bottom'].set_position('zero')
ax.spines['right'].set_visible(False)
ax.spines['top'].set_visible(False)
# Draw circle
circle = patches.Circle((0, 0),
radius=1,
color='black',
ls='dashed',
fill=False)
ax.add_patch(circle)
# Make a and b of equal length
a = numpy.append(a, numpy.repeat(0, max(len(a), len(b)) - len(a)))
b = numpy.append(b, numpy.repeat(0, max(len(a), len(b)) - len(b)))
# Plot poles
p = numpy.roots(a)
plt.plot(p.real, p.imag, 'kx', ms=7)
# Plot zeros
z = numpy.roots(b)
plt.plot(z.real, z.imag, 'ko', ms=7)
plt.axis('scaled')
plt.show()
def plot_freq_resp(self, a, b, worN=None):
w, h = signal.freqz(b, a, worN)
plt.plot(w, 20 * numpy.log10(abs(h)), 'b')
plt.ylabel('Amplitud [dB]', color='b')
plt.xlabel('Frecuencia [rad/muestra]')
plt.gca().twinx()
angles = numpy.unwrap(numpy.angle(h))
plt.plot(w, angles, 'g')
plt.ylabel('Fase (rad)', color='g')
plt.grid()
plt.show()