760 



1.0 

 0.9 



0.8 



THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1954 



5 0.2 



z 



-5 -4 -3-2-1 12 



tf MAX = 2tf, 



Fig. 25 — Comparison of impulse characteristics with fundamental and com- 

 bined fundamental and third harmonic cosine variation in delaj^ as in Fig. 24. 



the combined effect of the two sine deviations is obtained by first deter- 

 mining the effect of —V sin cor' from (6.05). The vakie of P(0 = -Pi(0 

 thus obtained from (6.05) Avith 6 = 5' and r = r' is next substituted for 

 Po(0 in (6.05), with h = h" and r = r" to evaluate the effect of -h" 

 sin cor". That is, the system is considered to consist of a tandem arrange- 

 ment of two components, the first with a phase distortion —6' sin cor 

 and the second wdth phase distortion —5" sin cor". 



In Fig. 24 is sho^vii a particular case in which the second component 

 is a triple harmonic of the first with amplitude h" = —0.04356'. This 

 results in an improved approximation to the delay distortion encountered 

 in certain wire facilities, where the band is sharpl}^ confined by filters. 

 In Fig. 25 is shown the pulse shape for this case with b' = 15 radians, 

 together \xith. that for a single sine deviation of 6 = 15 radians. 



It AAdll be recognized from the above that as the number of sine com- 



