SINGING ON TWO-WIRE CABLE CIRCUITS 



627 



or 



(5g(2)) X (S, 

 p 



s,) = SM)- 



It will be noted that Sg(<=o) = Sq{2.0). 



It should be noted that the values of Sg{d) corresponding to the 

 higher percentages may be considerably modified by the efifect of the 

 equipment return losses, particularly when d is large. However, this is 

 usually of no very great importance because it is the lower percentages 

 and the smaller values of d which are of the most practical importance. 



A 



A, 



B 



b 



d 

 E 

 El 



E, 



= F 



APPENDIX VI 



Nomenclature 



attenuation factor per loading section (current ratio), 

 attenuation factor per loading section (current ratio) 

 of k th repeater section from critical repeater. 

 S\i + Sii — Si 



= log 



20 



Si minus the average singing point on a group of lines, 

 the standard deviation of a group of singing point 



measurements. 

 05 — 04. 



net loss of circuit in db. 

 loss in end path toward West for zero terminal return 



loss. When primed, it is the loss at 1000 cycles, 

 same as Ei but toward East, 

 probability of obtaining a greater returned current 



then If from a randomly selected one of a group of 



lines. 



