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BELL SYSTEM TECHNICAL JOURNAL 



will be provided in the future. The frequency assignments for these 

 systems are shown in Fig. 1. 



The "staggering" advantage, or effective crosstalk reduction be- 

 tween systems, is effected because (1) the inversion or displacement of 

 channels in the different systems with respect to each other makes the 



1.0 



90 100 110 120 130 140 150 



FREQUENCY- KILOCYCLES PER SECOND 



Fig. 10 — Unamplified interaction crosstalk between two J circuits at an auxiliary 



repeater station. 



crosstalk unintelligible and (2) the reduction of the overlap between 

 channels results in less energy being transferred between them by 

 crosstalk. The net benefits of "staggering" obtained by the alloca- 

 tions shown in Fig. 1 range from about 6 to 16 db. 



The most effective pair assignments for the four types of J systems 

 can best be obtained from actual crosstalk data on the particular 

 sections of line involved. The "staggering" advantages obtained are 

 sufficient so that the highest remaining crosstalk will usually occur 

 between the like J systems operating on non-adjacent pairs. 



