VIDEO SYSTEM WITH POWER SUPPLY FOR SCREEN GRID RESPONDING TO SYSTEM AUTOMATIC ADYUSTMENT OF KINESCOPE VOLTAGE ACROSS (AAVA) SYSTEM

摘要

FIELD: television systems; sources of bias voltage across screen grid in TV systems with one or more picture tubes as display units. SUBSTANCE: screen-grid power system controlling its voltage as given function black level correction signal shapes jointly with AAVA adjuster double feedback circuit for black level adjustment by means of power amplifier and screen grid thereby maximizing or extending entire black level control range. In the process high-voltage potentiometer used for controlling the screen may be fully dispensed with or, if used, next adjustment after initial one is not required. Proposed screen voltage adjustment circuit provides for optimal operating characteristics of picture tube without increasing voltage across control grid, without blocking AAVA circuits and output transistor connected to subcarrier power amplifier. EFFECT: simplified screen-voltage adjustment circuit arrangement. 1 cl, 7 dwg