Video display system with shading circuit for selectively varying intensity of video display

In a video display system utilizing horizontal (V.sub.x) and vertical (V.sub.y) deflection signals and a video signal to produce a video display,

• a control circuit for selectively varying the intensity of the video display, comprising:
• first means responsive to the horizontal (V.sub.x) and vertical (V.sub.y) deflection signals for producing a plurality of signals including quadratic signal components corresponding to functions of (V.sub.x).sup.2, (V.sub.x V.sub.y) and (V.sub.y).sup.2 and linear signal components corresponding to (V.sub.x) and (V.sub.y);
• means for combining said plurality of signals with the video signal to produce a shaded video signal for controlling the intensity of the video display;
• and
• circuit means for varying the magnitude of said quadratic and linear components of said plurality of signals.

A method of shading a video display produced by horizontal and vertical deflection signals and a video signal to selectively control the intensity of the video display, comprising:

• combining the horizontal and vertical deflection signals to produce a first plurality of signal components corresponding to linear and non-linear functions of the deflection signals;
• combining the plurality of signals with the video signal to produce a shaded video signal;
• and
• adjusting the magnitude of the linear and non-linear components of the shading signals to control the intensity of the video display.