PHASE DISTORTION IN TELEPHONE APPARATUS 



495 



two parts as follows: The first part is an exact copy of the original wave 

 modified in amplitude by a factor cos a^ and delayed by dB/do:. The 

 second part is obtained from the original wave by shifting all of the 



(720O) 

 (540°) 



(360») 



a: (I80">J 

 O 



Z (0°} 



bJ 



< (-180°) 

 a. 



(-360°) 

 (-540°) 

 (-720°) 



j = 2irf 



Fig. 1 — ^Phase characteristics which introduce no distortion. 



(720°; 4 IT - 



(-540°J -3tt 



fV20") -4tT - 



(.i=2TT-r 



Fig. 2 — Phase characteristics which introduce no distortion equivalent to those of 

 Fig. 1 with connections to the load reversed. 



components of the original by 7r/2, multiplying the result by sin ao 

 and then delaying by dBldoi. ao is the value of the angle at the point 

 of intersection of the vertical axis. 



