Vertical Height Adjust Circuit for CRT Display
Original Publication Date: 1988-Jun-01
Included in the Prior Art Database: 2005-Feb-15
A vertical screen-size control circuit, which is suitable for a multi- vertical screen-size application, is disclosed using standard commercial vertical process IC and other components. The advantages of the circuit are: 1. More than two screen sizes can be adjusted by only one potentiometer only once. 2. High reliability due to using only one potentiometer. 3. Very stable temperature variation. A CRT display was recently required to have a capability of changing vertical screen size due to multi-frequency application, multi-font and format application, or compatibility with former products. Screen mode information comes from logic, a card or PC as a mode signal in digital or analog form directly, or is generated by decoding the polarity status of H-sync or V-sinc or both signals in a display.