NWiATIVE IMPKDAXCK TKLKrHOX K UKl'KATKRS 



1073 



impedance tlirouiih a mult iplyiiiu; and pluise shift operation. It will ho 

 inter(>stinj>; to ('\amin(> tlicsc boxes to see what faetors determine their 

 characteristics. 



THE E2 CONVERTER 



The E2 negative impedance converter is the same as the El. As dis- 

 cussed elsewhere^ it can be represented schematically as in Fig. 14(a) 

 and also in terms of the eciuivalent circuit of Fig. 14(b) if the coils are 

 assumed to be ideal. The conv(M-t(M- performs much like a transformer. 

 An impedance seen through it is not only transformed in magnitude by 

 the ratio of ] 1 — jU|8 1 to | 1 + m 1 it is also modified by the phase shift 

 of this factor which over the operating band of freciuencies approximates 

 180 degrees. The symbol m stands for the voltage gain of the electron 

 tube and /3 is the ratio of 1 to 1 + (1 juCR). If both C and R are large 

 /3 approaches unity in magnitude and the ratio of conversion approaches 

 1— /xtol+M-IfMis large compared to unity then this conversion ratio 

 approaches —1. This ratio of —1 is approximately realized in the E2 

 con\'erter, and therefore the conversion ratio is not changed appreciably 

 b}^ small variations in /u. 



U. = VOLTAGE GAIN 

 OF TUBE 



Ro = TUBE PLATE 

 RESISTANCE 



jwCR 



Fig. 14 — E2 Converter; (a) schematic and (b) equivalent circuit. 



