# -*- coding: utf-8 -*- import matplotlib.pyplot as plt import numpy as np import pywt from matplotlib.font_manager import FontProperties sampling_rate = 1024 t = np.arange(0, 1.0, 1.0 / sampling_rate) f1 = 100 f2 = 200 f3 = 300 data = np.piecewise(t, [t < 1, t < 0.8, t < 0.3], [lambda t: np.sin(2 * np.pi * f1 * t), lambda t: np.sin(2 * np.pi * f2 * t), lambda t: np.sin(2 * np.pi * f3 * t)]) wavename = 'cgau8' totalscal = 256 fc = pywt.central_frequency(wavename) cparam = 2 * fc * totalscal scales = cparam / np.arange(totalscal, 1, -1) [cwtmatr, frequencies] = pywt.cwt(data, scales, wavename, 1.0 / sampling_rate) plt.figure(figsize=(8, 4)) plt.subplot(211) plt.plot(t, data) plt.xlabel(u"time(s)") plt.title(u"300Hz 200Hz 100Hz Time spectrum") plt.subplot(212) plt.contourf(t, frequencies, abs(cwtmatr)) plt.ylabel(u"freq(Hz)") plt.xlabel(u"time(s)") plt.subplots_adjust(hspace=0.4) plt.show() print("exit")
