R. Wiegerink et al., VARIABLE-GAMMA CIRCUIT FOR COLOR-TELEVISION BASED ON THE MOS VOLTAGE-TRANSLINEAR PRINCIPLE, Analog integrated circuits and signal processing, 9(2), 1996, pp. 189-195
In this paper a variable-gamma system is discussed for application in
high-quality colour television receivers, A variable-gamma system can
significantly improve the quality of the video image by enhancing the
contrast in darker parts of the image without degrading the lighter ar
eas of the screen. The adjustment of gamma can replace the traditional
contrast and intensity adjustments. The main part of the variable-gam
ma system is a nonlinear function block, which is implemented by an MO
S translinear (MTL) circuit, This circuit was realized in a standard 2
.5 mu m CMOS process, The circuit operates at a single 5V supply volta
ge, The measured small-signal -3dB bandwidth is 20MHz, The circuit res
ponse is insensitive to temperature, which is an important property of
translinear circuits.