说明：  1. 掌握利用脉冲响应不变法设计IIR数字滤波器的原理和具体方法。 2. 加深理解数字滤波器与连续时间滤波器之间的技术指标转化。 3. 掌握脉冲响应不变法设计IIR数字滤波器的优缺点及使用范围
(1. Master the principle and specific method of designing IIR digital filter with impulse response invariant method. 2. Deepen the understanding of the technical index transformation between digital filter and continuous time filter. 3. Master the advantages, disadvantages and application scope of the design of IIR digital filter by the pulse response invariant method)