48 BELL SYSTEM TECHNICAL JOURNAL 



more readily obtained than from the equations and, in some cases, 

 the solutions for effective impedances and current and voltage ampli- 

 tudes are obtainable without further recourse to the equations. 



ACKN OWLEDGMENT 



The writers are indebted to several of their associates in the Bell 

 Telephone Laboratories for the use of unpublished material in this 

 paper. In particular, acknowledgment is due to Mr. R. S. Caruthers, 

 Mr. J. M. Manley, Dr. G. R. Stibitz, and Mr. R. O. Wise, who origi- 

 nally obtained some of the impedance and efficiency relations. 



