python/test/3rd/lpf.py

   1 #!/usr/bin/env python
   2 import os, sys
   3
   4 base = os.path.dirname(__file__)
   5 path = os.path.dirname(base)
   6 path = os.path.dirname(path)
   7 sys.path.insert(0, path)
   8 try:
   9     import numpy as np
  10     import matplotlib.pyplot as plt
  11 except Exception as e:
  12     print(e)
  13     exit()
  14
  15 import liba  # type: ignore
  16
  17 x = np.arange(0, np.pi * 10, np.pi * 0.1)
  18 x1 = np.sin(x) + 0.2 * (np.random.random(len(x)) - 0.5)
  19 x2 = x1.copy()
  20 lpf = liba.lpf(10, 0.01)
  21 for i in range(len(x2)):
  22     x2[i] = lpf(x2[i])
  23 plt.figure("Low Pass Filter")
  24 plt.plot(x, x1, "b-", x, x2, "g-")
  25 plt.savefig(os.path.join(base, "lpf.png"))
  26 plt.show()