Stages of Filter Design 1.Determine the specification of the desired properties of the system(filter). 2.The approximation of the specifications using(designing)a causal discrete-time system. 3.The realization of the system. ◆Our focus is on second step.(实验侧重3) Specifications are typically given in the frequency domain. 99 Stages of Filter Design ◆1. Determine the specification of the desired properties of the system(filter). ◆2.The approximation of the specifications using(designing) a causal discrete-time system. ◆3. The realization of the system. ◆Our focus is on second step.(实验侧重3) ◆Specifications are typically given in the frequency domain