A METHOD OF IMPEDANCE CORRECTION 



823 



auxiliary network. By using two resonant arms with closely adjacent 

 resonance frequencies still better susceptance correction could have 

 been secured. 



Filters which must operate in parallel are usually given x-termina- 

 tions. Since an x-termination can be thought of as being a one element 



1.2 



1.0 



0.8 



0.6 



04 



o 

 N 0.2 



o 



< 



t- 



2;-o.2 



o 

 tr> 



z> 



-0.6 



-0.8 



-1.0 



-1.2 



•1.4 



0.2 



0.4 



0.6 

 X 



0.6 



1,0 



Fig. 12 — Susceptance relations at the line terminals of a pair of parallel complementary 

 filters having 2-branch conductance controlling networks. 



conductance controlling network the method we are discussing can be 

 applied here also. It is interesting to note that the introduction of an 

 auxiliary susceptance controlling network considerably improves the 

 performance even of this well known circuit. The susceptance rela- 

 tions at the line terminals of a pair of parallel complementary .r-term- 

 inated filters are shown in Fig. 13, the arrangement of the curves being 

 similar to that of Fig. 12. The improvement can be estimated from 

 the magnitude of the auxiliary susceptance. 



