FIR 滤波器也称为有限冲击响应滤波器，它用当前和过去输入样值的加权和来形成它的输出, 如下所的前馈差分方程所描述的。



FIR 滤波器又称为移动均值滤波器, 因为任何时间点的输出均依赖于包含有最新的 M个输入样值的一个窗。由于它的响应只依赖于有限个输入, FIR 滤波器对一个离散事件冲激有一个有限长非零响应, 即一个 M阶 FIR 滤波器对一个冲激的响应在 M个时钟周期之后为零。

-FIR filter, also known as finite impulse response filter, it uses current and past input samples to form the weighted sum of the value of its output, as the feed-forward differential equations described. FIR filter, also known as moving average filters, because any point in time are dependent on the output of M contains the latest input sample values a window. Because of its response depends only on a limited input, FIR filter to a discrete event there is a finite non-zero impulse response, that is, an M-order FIR filter to an impulse response in the M clock cycles after the zero.