在python中应用巴特沃斯带通滤波器后，如何删除信号开头的大尖峰？

import numpy as np
from scipy.signal import butter, filtfilt
import matplotlib.pyplot as plt

order = 4  # 滤波器阶数
fs = 1000  # 采样频率
lowcut = 10  # 低频截止频率
highcut = 100  # 高频截止频率

def butter_bandpass_filter(data, lowcut, highcut, fs, order):
    nyquist = 0.5 * fs
    low = lowcut / nyquist
    high = highcut / nyquist
    b, a = butter(order, [low, high], btype='band')
    y = filtfilt(b, a, data)
    return y

t = np.linspace(0, 1, fs, endpoint=False)
data = np.sin(2 * np.pi * 30 * t) + np.sin(2 * np.pi * 60 * t) + np.random.randn(fs) * 0.1

filtered_data = butter_bandpass_filter(data, lowcut, highcut, fs, order)

plt.figure(figsize=(10, 6))
plt.subplot(2, 1, 1)
plt.plot(t, data, 'b-', label='Original Signal')
plt.xlabel('Time [s]')
plt.ylabel('Amplitude')
plt.legend()

plt.subplot(2, 1, 2)
plt.plot(t, filtered_data, 'g-', linewidth=2, label='Filtered Signal')
plt.xlabel('Time [s]')
plt.ylabel('Amplitude')
plt.legend()

plt.tight_layout()
plt.show()