python/test/hpf.py

   1 #!/usr/bin/env python
   2 import os, sys
   3
   4 sys.path.insert(0, os.getcwd())
   5 prefix = os.path.join(sys.path[0], "build")
   6 if not os.path.exists(prefix):
   7     os.mkdir(prefix)
   8 try:
   9     import liba as a
  10     import numpy as np
  11     import matplotlib.pyplot as plt
  12 except Exception as e:
  13     print(e)
  14     exit()
  15
  16 Ts = 1.0
  17 f_0 = 1.0
  18 f_e = 1000.0
  19 c = (f_e - f_0) / Ts
  20 T = 1.0 / 10000
  21 x = []
  22 x1 = 0
  23 while x1 < Ts:
  24     x.append(x1)
  25     x1 += T
  26 x1 = np.array(x)
  27 x1 = np.cos(2 * np.pi * (f_0 * x1 + 0.5 * c * x1 * x1))
  28 x2 = x1.copy()
  29 hpf = a.hpf(10, 0.01)
  30 for i in range(len(x2)):
  31     x2[i] = hpf(x2[i])
  32 plt.figure("High Pass Filter")
  33 plt.plot(x, x1, "b-", x, x2, "g-")
  34 plt.savefig(os.path.join(prefix, "hpf.png"))