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Gamma Correction Circuit

IP.com Disclosure Number: IPCOM000052011D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11

Publishing Venue

IBM

Related People

Authors:
Marple, WP [+details]

Abstract

The gamma characteristic of a CRT display is a nonlinear relationship between the light output of the CRT and the CRT video output voltage, as illustrated in Fig. 1. The gamma characteristic of typical CRT displays is a positive exponential curve. Since it is desirable to achieve a linear relationship between the CRT light output and the video input voltage, conventional gamma correction circuits employ a logarithmic transfer function which, when superimposed upon the exponential transfer function of the CRT itself, results in a linear characteristic. However, this linear characteristic for prior art circuits is difficult to maintain over large temperature ranges.