用重叠保留法和快速傅里叶变换计算一个长序列和一个短序列的线性卷积。它通常用于数字滤波。数字信号处理常用的哦！-With the overlap-save method and the fast Fourier transform calculation of a long and a short sequence of linear convolution sequence. It is typically used for digital filtering. Commonly used in digital signal processing, oh!