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BELL SYSTEM TECHNICAL JOURNAL 



Uk = — 1. the simulation is improved by dissipation, as we might 

 expect. 



This physical possibility of closely simulating the image impedance 

 of a wave-filter shows that the assumption of such a physical termi- 

 nation, as made in a previous paper,^^ was practically justified when 

 solving the problem of the behavior of wave-filters under non steady- 

 state conditions. 



Fig. 16— Simulation of the image impedances Wn and Wn- by the impedance net- 

 works of Fig. 15. (Broken lines are for dissipation with Vk = ± .01 Uh). 



The particular structures for simulating the impedances of "con- 

 stant k" low pass, high pass, low-and-high pass and band pass wave- 

 filters, which correspond to the general ones of Fig. 15, are obtained 

 by terminating the networks of Appendix II with resistances R. It is 

 understood, of course, that others than the "constant k" wave-filter 

 of any class have either the image impedance Wik or W2k. Obviously, 

 it would be possible to simulate the impedance of any wave-filter which 

 by proper combination on the image basis can be linked with these 

 networks simulating PI'u or W^k- This, therefore, gives a method for 

 obtaining in a limited frequency range or ranges almost any resistance 

 characteristic with zero reactance. 



Likewise, the impedance of a mid-series section of the shunt MM'- 

 type or a mid-shunt section of the series J/.l/'-type which has the 

 parameters of formula (32) and one pair of its terminals closed by a 



1^ "Transient Oscillations in Electric Wave-Filters," J. R. Carson and O. J. 

 /obel. B. S. T. J., July. 1923. 



