DISTORTION CORRECTION . 481 



Solution of the resulting four attenuation linear equations gave 

 Po = 102.007 -lO^; P2 = 5.06037 -lO'"'; 



from which 



Qo = 32.200-109; Q2 = 3.43087 -lO^; 



ao = .28054; ai = .88319-10-='; 



61 = 8.6884-10-='; 62 = 4.0094- 10-«. 



Then, where R = 600 ohms, the series elements in the lattice structures 

 are 



Rn = 248.40 ohms; C12 = 2.0171 mf.; 



Cn = .6021 mf.; Ru = 336.65 ohms. 



Transforming from this lattice type to the equivalent bridged-T (la) 

 type, we eliminate a parallel resistance in the bridged series branch 

 (corresponding to Ru) by letting 



c = 1/ao. (70) 



Then in Fig. 14, where c = 3.5645, 



Ri = 168.3 ohms; Rs = 248 A ohms; 

 a = 2.0171 mf.; C^ = .6021 mf.; 



and in the shunt branch 



R2 = 3037.4 ohms; P4 = 1458.1 ohms; 

 U = .243 h.; Lg = 2.010 h. 



This latter useful form in which resistances are in series with induc- 

 tances was obtained from the regular bridged-T (la) shunt elements 

 by means of Transformation C, B. S. T. J., January, 1923, p. 45. 



The high-frequency network, shown as the lower section in Fig. 14, 

 is well suited to extend the range of attenuation equalization above 

 that so far considered and was derived from Network 8, Appendix IV. 

 Allowing for both cable and low-frequency network attenuations, and 

 arbitrarily assuming this network to have an attenuation of .300 

 napier at 4500 cycles per second, the data became (as from (8)) 



/o = 0, Aq = .796 napier; 



/i = 3000 -, A I = .747 napier; 



/2 = 4000 '-, Ai = .530 napier; 



/s = 4500 -, Az = .300 napier. 



