THEORETICAL FI'XDAMEXTALS OF PULSE TRANSMISSION 



783 



that (10.02) becomes U = \ or 



,•1 



r - 



sill :^ u } (I — cos iSiH.') (hi 



1/2 



(10.11) 



The maximum delay distortion at the edge of the transmission liand, 

 i.e., CO = 2coi , is t/max = 2/3i/coi . The product of this delay distortion 

 with the maximum frequency /max = 2/i is dmax/max = 2j(3i/7r. For various 

 \-alues of maximum phase distortion /3i and the corresponding product 

 (/max/max , tlic followiug \-alues of rms intersj^mbol interference are ob- 

 tained b}' numerical integration of (10.11). (This integral can be ex- 

 pressed in terms of a number of Fresnel integrals, but numerical integra- 

 tion is simpler and sufficiently- accurate for the present purpose.) 



The particular case c/max/max = 8 is similar to that shown in Fig. 36, 

 except that this figure applies to a Gaussian characteristic, for which 

 the amplitude at oj = coi has been taken as 0.32 rather than 0.5 in the 

 case considered here. For this reason rms intersymbol interference from 

 phase distortion would be greater in the present case. 



FREQUENCY, CJ 



Fig. 38 — Typical transmission frecjuency characteristic with phase equaliza- 

 tion over 50 per cent of transmission band. 



