DISTORTION CORRECTION 



495 



tan {BI2)R , ^10 tan (B/l) , 

 Li = rrr ttih. ; 62= 5 mt . 



The results for the fixed sections follow in Table IV. 



TABLE IV 



Phase Corrector Constants 



(Fig. 22) 



Fixed Sections 

 (Degrees at 50 kilocycles per second) 



10 



20 



40 



80 



160 



Li (mh.) . . . . 

 C2 (10-3 i^f) 

 L3(mh.).... 

 Ci (10-3 mf.) 

 C, (10-3 mf.) 

 Le (mh.) . . . . 



.334 

 .464 



.667 

 .926 

 .309 

 .223 



1.333 



1.851 



.631 



.454 



1.211 

 1.682 

 1.456 

 2.023 

 1.051 

 .756 



2.941 

 4.084 

 2.466 

 3.425 

 2.408 

 1.734 



In any one of these sections the computed departures of the phase 

 constant from ideal proportionality to frequency in the frequency 

 range 50 to 65 kilocycles per second was usually much less than .02 

 degree. The practical construction of the networks gave similar high 

 precision, and by using coils of small dissipation constant, d = (re- 

 sistance/reactance), the attenuation requirements were likewise satis- 

 fied. The frequency band now in use is from 58.5 to 61.5 kilocycles 

 per second. 



It may be added that these designs can readily be altered so as to 

 apply to other frequency ranges. In order to translate the phase 

 constants from the 50-kilocycle designation to any other frequency 

 range with a minimum frequency, /o, designation, multiply all induc- 

 tances and capacities by the translation factor (50,000//o).^'' 



4.7. Simulation of Smooth Line 

 This application is based upon and illustrates the general results 

 of Part 3 which discusses recurrent networks having arbitrary iterative 

 impedances. A network design will be given which has the following 

 characteristics. 



1. A propagation constant which simulates a moderate propagation 

 length of any smooth line, or its equivalent. 



1^ For a discussion of other applications of constant resistance networks see 

 footnote 10; also "Transmission Circuits for Telephonic Communication," K. S. 

 Johnson. 



