Control circuitry for video amplifier - corrects brightness of amplified video signal using stored correction valves

摘要

The video amplifier (1) comprises a differential amplifier provided with resistance network (2, 3, 20) for circuitry amplification. A video signal is provided at the input of the amplifier (1) and the output is fed to an a-d converter (4), the output of which is fed to a compensator (9) for correcting brightness. The compensator is connected, via a d-a converter (10) and an amplification stage (12), to the reference input of the video amplifier (1). The output of the compensator is also connected to the resistance network of the amplifier via an arithmetic stage (13) which pref. has a synchronisation input connected to the video signal source via a logic circuit (12). USE/ADVANTAGE - Data processing systems for digital image processing, e.g. in high precision photometry. Esp. good for correction of dark and light video signals. No standardising signal needed. Long term stability of correction data. Good quality signals processed quickly and inexpensively.