我想使用带通滤波器去趋势我的信号,所以我在 python 中使用了 FL=0.1 Hz 和 FH=20Hz 的 Butterworth 滤波器,但是在应用这个带通滤波器后,我观察到信号开始处的大尖峰。这个尖峰是做什么用的?以及如何删除python中的这个尖峰?
您可以从此链接下载“data1.csv” 。
from scipy.signal import butter, lfilter
from numpy import genfromtxt
import numpy as np
import matplotlib.pyplot as plt
def butter_bandpass(lowcut, highcut, fs, order=5):
nyq = 0.5 * fs
low = lowcut / nyq
high = highcut / nyq
b, a = butter(order, [low, high], btype='band')
return b, a
def butter_bandpass_filter(data, lowcut, highcut, fs, order=5):
b, a = butter_bandpass(lowcut, highcut, fs, order=order)
y = lfilter(b, a, data)
return y
BP_without_NaN = genfromtxt('data1.csv', delimiter=',')
framerate=1024
# detrending [0.1Hz 20Hz]
OMW = butter_bandpass_filter(data = BP_without_NaN, lowcut = 0.1, highcut = 20 , fs = framerate, order = 3)
# plot OMW
time = np.linspace(0, len(OMW)/framerate ,len(OMW))
plt.plot(time, OMW)
plt.show()