Python+matplotlib实现计算两个信号的交叉谱密度实例

import numpy as np
import matplotlib.pyplot as plt


fig,(ax1,ax2) = plt.subplots(2,1)
# make a little extra space between the subplots
fig.subplots_adjust(hspace=0.5)

dt = 0.01
t = np.arange(0,30,dt)

# Fixing random state for reproducibility
np.random.seed(19680801)


nse1 = np.random.randn(len(t))         # white noise 1
nse2 = np.random.randn(len(t))         # white noise 2
r = np.exp(-t / 0.05)

cnse1 = np.convolve(nse1,r,mode='same') * dt  # colored noise 1
cnse2 = np.convolve(nse2,mode='same') * dt  # colored noise 2

# two signals with a coherent part and a random part
s1 = 0.01 * np.sin(2 * np.pi * 10 * t) + cnse1
s2 = 0.01 * np.sin(2 * np.pi * 10 * t) + cnse2

ax1.plot(t,s1,t,s2)
ax1.set_xlim(0,5)
ax1.set_xlabel('time')
ax1.set_ylabel('s1 and s2')
ax1.grid(True)

cxy,f = ax2.csd(s1,s2,256,1. / dt)
ax2.set_ylabel('CSD (db)')
plt.show()