低通滤波器的Python代码

以下是一个简单的低通滤波器的Python代码示例：

import numpy as np
import scipy.signal as signal

# 生成信号
t = np.linspace(0, 1, 1000, endpoint=False)
x = np.sin(2 * np.pi * 10 * t) + np.sin(2 * np.pi * 20 * t)

# 设计低通滤波器
cutoff_freq = 15  # 截止频率15Hz
nyq_freq = 0.5 * 1000  # 采样频率500Hz的奈奎斯特频率
cutoff_normalized = cutoff_freq / nyq_freq  # 归一化截止频率
b, a = signal.butter(4, cutoff_normalized, btype='lowpass')  # 4阶巴特沃斯低通滤波器

# 应用滤波器
filtered_x = signal.filtfilt(b, a, x)

# 绘制滤波前后的信号对比
import matplotlib.pyplot as plt

fig, ax = plt.subplots()
ax.plot(t, x, label='Original')
ax.plot(t, filtered_x, label='Filtered')
ax.legend()
plt.show()

输出图像如下：