音频信号通过LM386放大，仿真图是速度、距离、幅度三维图像，FIR 底通和带通滤波器和IIR 底通和带通滤波器。- LM386 audio signal amplification, FIG simulation speed, distance, amplitude three-dimensional image, Bottom-pass and band-pass FIR and IIR filter bottom pass and band-pass filter.