Ex.7.1 Determining Specifications for a Discrete-Time Filter Solution: H(e) Specifications of the Same tolerance limits: 1+δp1d discrete-time filter in δn=δp20.01 1-0p2 Hleo）Hn9}Hn(U2) 频率响应相等不变 幅频指标不变 Passband Transition Stopband Hw(U2 δ=0.001 I+ 变换截止频率 0p2 0. 6.4π 0、=0.6π Passband Transition Stopband 0=2T=104Ω 2,=2π(2000) 2.=2π(3000) T=104s 0.001 0 n, 2 T15 Ex. 7.1 Determining Specifications for a Discrete-Time Filter 4 T s 10− = 4  T 10− = =  Specifications of the discrete-time filter in    P P 1 2 = =0.01 S =0.001 2 (2000)  = p  2 (3000)  = s  0.4   p = 0.6   s = Solution: Same tolerance limits: H j eff ( ) ( ) j H e  1+ P1 ( ) eff eff ( ) ( ) j H H j H T e j   1− P2 = =   S 1+ P1 1− P2  S 0.001 0.01 幅频指标不变 变换截止频率 频率响应相等不变