347 11.5 Block Diagrams arid State-Space Figure 14.7: Direct ii,rm of a tfkcrete LTJ-syst,rm escr~ptiQ for~ Discrete If a block diagram of an LT1-system is given, a state-spacc representation of the form (14.26) (14.27) rail be formalated As state vector ~ [ kthe ] vdnes stored in the delay circuits are chosen W e c d l (14.Xi) the s y r t t m ecpation, which ckscribes changes in the intcriid states depending on the current state zik]and the input series x [ k ] With the form (14.26) arid (14.27) it is easy to charzractcrise systems with multiple inputs niid outputs (Figure 14.10) Using thc z-transform on the state-space d ription (14.26),(14.27) -vve obtaiIi: (14.28) (14.29) Thesc cquations are identical to the stat,e-spacx! description of U continuous-tine systern in the l,;i,place-tlornain cxwpt that the complex variable s has in this case