巴特沃斯滤波器，主要实现的是低通信号，此功能模块的低通曲线很符合理想的幅频特性。-Butterworth filter, the main achievement is low traffic numbers, the low-pass curve is consistent with this function module ideal frequency characteristics.

在智能化交通上如何做到区别噪声和汽车鸣笛声，为智能无人车的安全通畅行驶提供有力的保证。本程序通过滤波器的波形判断声波是否属于汽车鸣笛声。(In the intelligent traffic, how to make the noise and the sound of the car whistle can provide a powerful guarantee for the unobstructed driving of the intelligent unmanned vehicle.