岩石次声滤波处理新技术——Sallen-Key数学模型

A novel filter technology of rock's infrasound:Sallen-Key numerical model

为研究岩石破裂发射次声波信号的频率分布特征,高效可靠的数字低通滤波技术是必要的研究环节。针对模拟滤波器电路的参数确认复杂、自激振荡影响等不良因素,对模拟Sallen-Key有源滤波电路进行分析、推导并建立了Sallen-Key低通滤波器的时域离散数学模型。仿真试验结果表明:Sallen-Key数字低通滤波模型可以有效地提高信噪比,并避免了模拟滤波电路引起的自激振荡现象。对岩石破裂次声波进行低通滤波处理,并与传统ButterWorth数值滤波进行了比较,结果证明Sallen-Key数学模型是一种非常有效的数字信号处理方法。

In order to reveal the frequency distribution characteristics of infrasound signal emitted by rock＇ s fracture, a digital low-pass signals filtering technology with high efficiency and reliability was investigated in this study. Considering the complexity of analog filter circuit parameters, the self-vibration and other adverse effects, the authors developed the time-domain discrete mathematical model of the Sallen-Key active filter circuit based on the analysis of circuit principle. The simulation results show that the Sallen-Key digital low-pass filter model can effectively improve the signal-to-noise （S/N） ratio, and avoid the self-excited oscillation phenomenon caused by the analog filter circuit. Compared with the traditional Butterworth filter algorithm, the results show that the new digital model is an effective digital signal processing method in noise reduction.