Variable Exponent Type Gamma Correction Circuit

Abstract

To improve color reproducibility in computer monitor display and television receiver, an analog gamma correction circuit with not approximate but accurately exponent conversion characteristic has been developed. It consists of a logarithm converter, a variable gain amplifier and an exponent converter. Owing to making the most effective use of characteristics in differential bipolar transistor circuits, the gamma correction circuit has a small size configuration and high speed characteristics in signal processing. Its exponent gamma value is easily changeable from less than 0.1 to more than 3.1, and its frequency width is obtained 125 MHz on bread board. Consequently, it has expected to become possible that white balance adjustments for the displays are precise enough to use them in color matching applications, and color reproductions in displays of many devices are stable independently of adjustments by users too.