86 lines
2.1 KiB
Python
86 lines
2.1 KiB
Python
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# %%
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import logging
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from abc import ABC, abstractmethod
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from pathlib import Path
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from typing import Tuple, Union
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import numpy as np
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from matplotlib import pyplot as plt
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from matplotlib.animation import FuncAnimation
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from matplotlib.axes import Axes
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from matplotlib.figure import Figure
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from matplotlib.gridspec import GridSpec
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from scipy import signal
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# %%
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def db20(x):
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return 20 * np.log10(x)
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# %%
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wpass = 20 * 2 * np.pi
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wstop = 30 * 2 * np.pi
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gpass = 2
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gstop = 30
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o, wn = signal.cheb1ord(
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wpass,
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wstop,
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2,
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30,
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analog=True,
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)
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zpk_cheb1 = signal.cheby1(o, gpass, wn, analog=True, output="zpk", btype="lowpass")
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o, wn = signal.cheb2ord(
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wpass,
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wstop,
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gpass,
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gstop,
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analog=True,
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)
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zpk_cheb2 = signal.cheby2(o, gpass, wn, analog=True, output="zpk", btype="lowpass")
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o, wn = signal.buttord(wpass, wstop, gpass, gstop, analog=True)
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zpk_butter = signal.butter(o, wn, btype="lowpass", analog=True, output="zpk")
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o, wn = signal.ellipord(wpass, wstop, gpass, gstop, analog=True)
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zpk_ellip = signal.ellip(o, gpass, gstop, wn, btype="lowpass", analog=True, output="zpk")
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# %%
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fig = plt.figure(layout="constrained")
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gs = GridSpec(2, 2, figure=fig)
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ax_zp = fig.add_subplot(gs[:, 0])
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ax_f = fig.add_subplot(gs[0, 1])
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ax_t = fig.add_subplot(gs[1, 1])
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for z, p, k in [
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zpk_cheb1,
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# zpk_cheb2,
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zpk_butter,
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zpk_ellip,
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]:
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lines_z = ax_zp.plot(np.real(z), np.imag(z), "o", mfc="none")
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lines_p = ax_zp.plot(np.real(p), np.imag(p), "x", color=lines_z[0].get_color())
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# plt.xlim(-150, 150)
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ax_zp.grid(True)
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ax_zp.set_xlabel("Real(s)")
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ax_zp.set_ylabel("Imag(s)")
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f = np.linspace(0.1 * np.max([wpass, wstop]), 10 * np.max([wpass, wstop]), 1001) / (2 * np.pi)
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ax_f.semilogx(f, db20(signal.freqs_zpk(z, p, k, f * 2 * np.pi)[1]))
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ax_f.grid(True)
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ax_f.set_xlabel("Frequnecy [Hz]")
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ax_f.set_ylabel("Gain [dB]")
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ax_f.set_xlim(f[0], f[-1])
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# t = np.arange(101)
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# x = np.zeros(len(t))
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# x[int(len(x) / 2)] = 1
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# ax_t.plot(t, signal.lfilter(*ba, x))
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# ax_t.set_ylim(-10, 100)
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# ax_t.grid(True)
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# %%
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