100 THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1957 



CO 



_l 

 UJ 



o 



LU 



a 



20 40 60 80 100 120 140 160 



FREQUENCY IN KILOCYCLES PER SECOND 



160 200 



Fig. 23 — Equalizer loss characteristics. 



pedance type equalizers to avoid the necessity for shunt arms and the 

 accompanying high-voltage blocking capacitor required to isolate the 

 cable power circuits. This restriction confines the ultimate location of 

 the equalizers to the middle portion of repeater sections to minimize the 

 reaction of the poor repeater impedance on the equahzer characteristic. 

 The dc resistance of equalizers is low so that material increase of the 

 system power supply voltage is not required. 



The configuration of two of the equalizers are shown in Fig. 22. The 

 loss characteristics are shown in Fig. 23. Each equahzer has a maxi- 

 mum loss spread in the pass band of about 4 db which represents a com- 

 promise between keeping the number of equaUzers low and at the same 

 time keeping the misalignment within tolerable hmits. 



The components used are modifications of the repeater components. 

 The mechanical construction is identical to the repeater except that with 

 the smaller numljer of elements, the container is materially shorter than 

 a repeater. 



ACKNOWLEDGMENTS 



Scores of individuals have contributed to the development of these 

 repeaters, some leading to basic decisions, some creating, adapting and 



