THEORETICAL FUNDAMENTALS OF PULSE TRANSMISSION 



759 



ingly negative with respect to (/,„ax = used for reference. The curves 

 apply to u band-pass system as indicated in the figure, and also to a 

 low-pass system having the delay distortion shown above the midband 

 freciiiency of the band-pass sj'stem. 



An improved approximation to phase distortion is sometimes obtained 

 by considering two sine deviations in the phase characteristic. 



If the phase characteristic is given by 



\l/((jj) = i/'o(co) — h' sin o)T — b" sin ut, 



(6.11) 



b =-0.0435 b 



(a) PHASE DISTORTION 



// (b) DELAY DISTORTION 



d MAX = 0.85 d MAX 



UJ 



Q -0.2 



LL 



o 



Q -0.4 



5 -0.6 

 < 



p -0.( 

 < 



-1.0 -O.S -0.6 -0.4 -0.2 0.2 0.4 0.6 0.8 1.0 



f/fMAX = f/2fl 



P'ig. 24 — Shape of delay distortion with combined fundamental and third 

 luirmonic cosine variation in delay. 



