Wiley signals and systems e book TLFe BO 349

F'igiiri- 1311: Enact frequrncy rrsponsr to (1 3.28) and the estimate from t,ho polc-zero d iagr a m Substituting z = into (13.28) gives A- = -1 The estimates are show11 in Figwe 13.11 with the exact t for comparison, Zeros lying tiirertly or1 the unit cirrle forcc7 the magnitude o Fourier tiensforrn at this f r ~ q w r i c yto zero, and [ d e s lying w a r to tlw niiit circle incrraso the uiiit, circle that a pcrle 01 x r o lies, the greater PB it, has on thc h"mr.ier transform Poles 01 zeros at the origin of the z-plane hav influence oil h ma,gni( ude of the Four ic.1 trarisforin, hiit they inakc ~1 h e a r roni rihut ion towards tlrc phase