数字滤波器的设计及性能比较　
用三种方法设计FIR滤波器：窗口法、最大最小误差法、频率采样法；用两种方法设计IIR滤波器：冲激响应不变法、双线性变换法。很全的matlab滤波器程序！,　 Digital filter design and performance comparison of three methods to use　 FIR filter design: the window method, the largest minimum error method, frequency sampling method　two ways IIR filter design: impulse response of the same law, two and transform. Is the whole process of the matlab filter!