说明：  设计一个16阶的低通FIR滤波器，对模拟信号的采样频率Fs为48KHz，要求信号的截止频率Fc=10.8kHz，输入序列位宽为9位（最高位为符号位）。
(The FIR number filter example, designs a 16 ranks of low the FIR filter is a 48 khzs to the sample frequency Fs that imitates signal and request the closing of signal the frequency Fc=10.8 khzs, input a sequence breadth is 9.(the tallest is sign) )