1 # 7_20.py 2 3 import numpy as np 4 import matplotlib.pyplot as plt 5 from scipy import signal 6 7 fs = 400 8 T = 1/fs 9 t = np.arange(0, 1, T) 10 11 x_a = np.cos(2*np.pi*100*t) 12 x_b = (1 + np.cos(2*np.pi*10*t)) * np.cos(2*np.pi*100*t) 13 x_c = np.cos(2 * np.pi * 100 * t**2) 14 15 sig = [x_a, x_b, x_c] 16 17 plt.figure(figsize=(15, 5)) 18 19 for i, x in enumerate(sig): 20 plt.subplot(1, 3, i+1) 21 22 # `nperseg` tamaño de la ventana 23 # `noverlap` solapamiento entre ventanas 24 f, times, Sxx = signal.spectrogram(x, fs, window='hann', 25 nperseg=128, noverlap=32) 26 27 plt.pcolormesh(times, f, 10*np.log10(Sxx), cmap='inferno', shading='gouraud') 28 29 if i == 0: 30 plt.ylabel('Frecuencia [Hz]') 31 plt.xlabel('Tiempo [s]') 32 33 plt.tight_layout() 34 plt.show()
