152 



BELL SYSTEM TECHNICAL JOURNAL 



When the shunts are connected, the inductance around 1-5-6-2 is 

 lowered slightly, and the effective resistance is increased. To simplify 

 the capacitance loading and in order not to introduce more resistance in 

 one cable pair than another, the balancing coil assembly is so arranged 

 that shunted and non-shunted windings are alternately introduced 

 into a pair. 



5.5 



5.0 



4.5 



t 4.0 

 O 



3.5 



< 3.0 



2.0 



1.5 



2 4 6 8 10 12 14 16 18 20 



NUMBER OF TURNS OF ADJUSTING SCREW 



Fig. 10 — Series inductance of non-shunted trial balancing coil. 



Balancing Panels 

 In assembling the balancing coils on panels, the same number of 

 coils should be traversed on each of two pairs before reaching the coil 

 that balances these two pairs, in order that the phase shift up to this 

 balancing coil on one pair will be essentially the same as that on the 

 other pair. If these phase shifts differed materially, the coil setting 

 for minimum crosstalk when one pair is the disturbing circuit might be 

 quite different from the best setting when the other pair is the dis- 

 turbing circuit. To obtain this equality objective a "criss-cross" ar- 

 rangement, as shown schematically on Fig. 11, was devised, whereby 

 the number of coils on one pair up to a particular balancing coil never 

 differs by more than one from the number of coils on the other pair up 

 to this same balancing coil. 



