用窗函数法设计一个能对模拟信号进行滤波的线性相位FIR低通滤波器。抽样频率为 kHz，通带截止频率为 kHz，阻带截止频率为 kHz，要求阻带最小衰减 dB。为了降低运算量，所设计滤波器的阶数要尽可能的低-With the window method to design a filter to the analog signals of linear phase FIR low-pass filter. Sampling frequency is kHz, passband cutoff frequency kHz, stopband cutoff frequency of kHz, the minimum required stopband attenuation dB. To reduce the computation, the order of the filter designed to be as low as possible