输入一个低频率的正弦波和一个高频的正弦波叠加而成,通过观察频域图和时域图,低频波通过了滤波器,高频大部分被滤除-input of a low-frequency sine wave and a high-frequency sine wave overprinted, By observing frequency domain and time domain map plan, low-frequency waves through the filter, the majority of hig