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BELL SYSTEM TECHNICAL JOURNAL 



in Fig. 8; the corresponding limiting forms of the excess-simulators 

 are considered a little further on. 



Fig. 9, derived from Fig. 8, represents the optimum value of D 

 as function of F; and shows also the corresponding minimum de- 

 parture 8 m of the complete network. If D is chosen to be the optimum 



Opt.D 



'm 



1.2 1.6 2.0 2.4 



F-ojl/r 



Fig. 9 



value at any fixed F, the resulting network will have at that F exactly 

 the departure shown on Fig. 9, but at all other values of F will, of 

 course, have departures larger than those on Fig. 9. 



It should be noted that these statements regarding the departures 

 pertain to the network when the excess-simulator is proportioned in 

 accordance with formulas (32), . . . (37). As those are only first- 

 approximation formulas, the ultimate precision attainable will usually 

 be better, and may be adjusted to possess a somewhat different dis- 

 tribution over the frequency-range. 



Although the two excess-simulators in Fig. 7 are potentially equiva- 

 lent as regards impedance there is a slight choice between them from 

 the viewpoints of cost and space occupied. For it is readily seen by 

 mere inspection of the networks at zero frequency that when they have 

 equal impedances the total capacity C2+C3 of the excess-simulator 

 in Fig. 7a is equal to merely the capacity C t of the excess-simulator 

 in Fig. 7b, thus leaving C : , in excess. As regards the relative magni- 

 tudes of their various elements the two excess-simulators can be 



