PHASE DISTORTION IN TELEPHONE APPARATUS 



511 



FREQUENCY 

 1.2 1.4 



Fig. 20 — Insertion phase characteristics and schematics for high-pass filters. {A) 

 For a filter consisting of 3 full sections, one section having no attenuation peak, one 

 with a peak at 1/1.25/c and another at 1/1.05/c. (S) Same as {A) with the 1/1.05/c 

 section omitted. 



10 



<3. 3 6 



■01 T> 



u 

 -^ 5 



>- 

 < 

 -I 4 



0.6 



0.8 



1.2 1.4 



FREQUENCY 



(^c) 



1.6 



1.8 



2.0 



50 



45 



40 



35 



30 



25 



20 



15 



10 



2.2 



Fig. 21 — Insertion delay and attenuation characteristic for filter .4 of Fig. 20. 



