A METHOD OF IMPEDANCE CORRECTION 



819 



and ai, a^ this condition can also be written in the form 



^ (1 - ai^) = a22[4(l - a,a,y + a,K\ - a,a,)J. 



A second condition upon these quantities is found by specifying the 

 range within which the impedance is to remain as flat as possible. 

 The results of computations to determine this relationship are given 

 in Fig. 8. x^ in this diagram signifies the highest value of x in the 

 operating range. Fig. 8 also gives the maximum departure of the 

 conductance characteristic from its ideal value as a function of Xq. 

 Numerical data taken from these curves should of course be confirmed 

 by the equations given herewith before they are used to specify element 

 values. 



Susceptance Correcting Networks ^ 



Once the conductance controlling portion of the network has been 

 determined by one or another of these methods our general procedure 

 calls for the computation of the susceptance characteristic it furnishes 

 and the design of a final shunting reactance network which will annul 



o 

 N 

 X 



UJ 



o 



z 

 < 

 (- 



Q. 



UJ 



o 

 w 



3 

 10 



cc 

 o 



1.4 



1.2 



1.0 



0.8 



0.6 



|n° 



z 

 < 



< 



UJ 



a. 



0.4 



0.2 



0.1 



0.2 



0.3 



0.4 



0.7 



0.8 



0.9 



1.0 



0.5 0.6 



X 



Fig. 9 — Reactance and susceptance characteristics secured from binomial expansion. 



^ This section gives only a general description of the characteristics required of the 

 susceptance correcting networks and the configurations which have been found 

 appropriate for them. The design of these networks may be conveniently approached 

 by means of the formulae contained in R. M. Foster's article "A Reactance Theorem," 

 in the Oct. 1924 issue of this Journal. 



