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BELL SYSTEM TECHNICAL JOURNAL 



grid circuits so that the applied grid drive and developed plate voltages 

 may be read directly. Of course, the gain figure arrived at in this man- 

 ner is an over-all factor, a function both of tube conditions and circuit 

 construction and loading. Nevertheless, it is a satisfactory figure of 

 merit for the stage. In Table III are shown these gain figures for a 

 typical tube under various conditions. 



Fig. 16^ — Distortion measuring equipment. 

 Nos. 1 and 2 — Signal oscillators. 



3 — Capacitance bridge. 



4 — Auxiliary amplifier. 



5- — Power supply unit for auxiliary amplifier. 



6 — Transmission lines to tube under test. 



7 — Transmission line from tube under test to radio receiver. 



8— Beating oscillator, first detector and attenuator. 



9 — Intermediate amplifier and second detector of receiver. 



