Design of a Raster Display Processor for Office Applications

In recent years there has been a pronounced emphasis to develop alphanumeric display systems for document creation, filing, and text editing applications. This paper describes the design of a raster scan Display Processor which was specifically implemented to produce full page images ( 8½ in × 11 in or 11 in × 8½ in) which emulate typewriter output. A dual data path architecture is presented in which a Character Generator produces video images of text data, while a FAX Generator generates bit map video images corresponding to graphic forms used in the office. The design approach chosen provides degrees of functional richness that are not commonly present in current systems. Furthermore, the modular approach allows for a choice of whether or not to include forms overlay capability based on application requirements.