6.1 Block Diagram Representation of Linear Constant-Coefficient Difference Equations yIn]=ayIn-I]axInj+axIn-1] 迭代地，反复地 Implementation of an lTI system by iteratively evaluating a recurrence formula needs three basic elements: 递推公式 system function Unit Delay x[n] x[n-1] (Memory,storage) Multiplier x[n] bo x2[n]=bx[n-1] Adder x1[n] x[n]+x2[n] =boxIn] =bx[n-1]+bx[n-1] 99 6.1 Block Diagram Representation of Linear Constant-Coefficient Difference Equations + x1 [n] x2 [n] x1 [n] + x2 Adder [n] x[n] b0 Multiplier b0x[n] x[n] x[n-1] z Unit Delay −1 (Memory, storage) y n ay n b x n bx n  = − + + −  1 1  0 1     Implementation of an LTI system by iteratively evaluating a recurrence formula needs three basic elements: M sample system function 递推公式 =b0x[n] =b1x[n−1] =b0x[n−1]+b0x[n−1] 迭代地,反复地