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THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1954 



ujr <JJrx\ FREQUENCY 



(a) FREQUENCY CHARACTERISTIC 



(b) IMPULSE CHARACTERISTIC 



Fig. 14 — Sj'mmetrical band-pass characteristic with linear phase shift and 

 corresponding impulse characteristic. In-phase and quadrature components 

 shown with respect to ojr = co„, — co^ . 



respect to a reference frequency at the midpoint of the band-edge are 

 obtained from (2.19) with 0)^ = 0)^. This gives P{t) cos bi^U for the in- 

 phase and P sin wM for the quadrature component. 



In Fig. 15 is shown a special case of a band-pass characteristic, which 

 corresponds to that ilhistrated in Fig. 9 with wi = 2wo , shown for com- 

 parison by dashed hnes in Fig. 15. In this particular case co„, = 3 coo/2 

 and coj = cos = 600/2. With \/'o = n-K, equation (4.08) in conjunction with 

 (4.09) gives 



„. X ^wo ( , /o\ sin 2coo^o — sin coo^o 

 rKt) = ::r- cos (cooV2) 



27r 



aJoi[l — (coo^o/tt)^] 



(5.04) 



