ARTIFICIAL ELECTRIC LINES WITH MUTUAL INDUCTANCE. 



201 



current any desired time-retardation substantially independent of the 

 frequency over a significant range of frequencies. 



An artificial line consisting of inductances in series and capacities 

 in shunt and provided with suitable switching devices is an electric 

 compensator. To have practical application the attenuation of the 

 compensator must be low and the steps must be made small enough 

 in inductance and capacity values to obviate filtering effects, and the 

 dimensions of the coils must be chosen in a manner to diminish dis- 

 persion and other distortions. The principles governing the design of 

 such a compensator are given in my book Electric Oscillatwns and 

 Electric Wares, pp. 285-323. 



It is proposed here to show how improvements result from the use 

 of suitable mutual inductance between the neighboring series induc- 

 tances of the electric compensator. 



10. Proof that Introduction between neighboring sections 

 of Mutual Inductance Approximately Equal to One-Tenth of 

 the Self Inductance of the Series Elements Greatly Reduces 

 Dispersion in an Electric Compensator. — It is proposed to prove 



LJ^ 



M 



Li 



l-i 



T-i 



M 



t-ilz 



^W^^^T^^SWA^V^^^^^^^ 



Q 



Figure 3. 



that mutual inductance between adjacent series inductive sections 

 of the value specified in the caption reduces dispersion; that is, that 

 it makes T, the time retardation per section, less dependent on the 

 frequency of the impressed e.m.f. 



The line to be employed has inductive elements in aeries and capa- 

 city elements in shunt, as is shown in Figure 3. The series elements 

 have an inductance L\ and resistance R\ per loop, and the shunt 

 elements have each a capacity C\. Let there be mutual inductance 

 M between the inductances of each two adjacent loops, and let there 

 be zero mutual inductance between inductances not adjacent. 



