Improvements in or relating to radio direction finding apparatus

Abstract

Abstract 528,061. Directive wireless signalling. WILLANS, P. W., and PLESSEY CO., Ltd. April 21, 1939, No. 12064. [Class 40 (v)] Automatic gain control is applied through a pilot current to the amplifiers used in a directionfinding system for feeding a direct-reading indicator, such as a cathode ray tube. The signal voltages are applied to the two amplifiers 10, 11, together with a "pilot" frequency indicated at 14, and the output is passed through coils 16 to a directional indicator (not shown). The pilot frequency is also applied through a transformer 22 to the anodes of two gain-control valves 19, 20. Any variation in the gain of the amplifiers 10, 11 will produce an unbalanced voltage in a coil 18 which is coupled to the grids of the valves 19, 20. This, in combination with the pilot frequency on the anodes of those valves, produces a biasing voltage across the anode resistance 21. The latter is connected through leads 24, 25 respectively to the grids of the main amplifiers 10, 11 and serves to equalize the gain of both. Specification 385,982, (Group XXXVI), is referred to.

Inventors

No inventors recorded.

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