398 



HELL SYSTEM TECHNICAL JOURNAL 



100 200 300 4-00 500 600 700 800 900 1000 



Kig. 6^Sheet I 



Sheets I and II of I-"ig. 6, taken together, show the impedance domain of the network 

 at the bottom of the opposite page, made up of three fixed resistances and two 

 varialjle reactances. The dashed curve, appearing in four distinct parts, two on 

 each sheet, shows the impedance .V when /; is the doubly-resonant circuit of Fig. 3b, 

 and Z| is an inductance of I.O henry. Points on this curve are labelled in terms of 

 frequency 



