FIR函数通过定义的系数和延时线来实现有限脉冲响应FIR滤波器。该函数产生了对输入数据的响应。该过滤器（通带，阻带等特点）由系数和抽头数决定。-FIR function by defining the coefficients and delay line to achieve the finite impulse response FIR filter. The function of the input data generated response. The filter (passband, stopband and so on) coefficient and the number of taps by the decision.