780 



THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1954: 



distortion were determined, indicates that the peak factor is about 3 

 when phase distortion is appreciable and the pulses are substantially 

 prolonged in duration. 



Returning to equation (8.17) and assuming a = 0, the following rela- 

 tionship is obtained for rms intersymbol interference due to phase devia- 

 tions 



U = r-^ f — Y " r f 2Ao-(l - cos /3) do: 

 ~~ "(0) \7rri/ L-^o 



(10.01) 



where |S = |S(co) is the deviation from a linear phase characteristic. 



For transmission S5^stems with a linear phase shift, the peak amplitude 

 of the pulses is given by (8.23) and with this relation in (10.01) 



Win 



X, 



where 



=hr 



2 A 0^(1 - cos /3) f/w 



1/2 /r 



//. 



Aoch 



(10.02) 



(10.03; 



UNDISTORTED PULSE 

 -(NO BAND-EDGE PHASE DISTORTION) 



AMPLITUDE 

 CHARACTERISTIC 



PULSE DISTORTION FROM 

 BAND-EDGE PHASE DEVIATION 



Fig. .36 — Pulse distortion from band-edge phase deviation for particular case 

 of linear band-edge delay distortion. 



