CRT Image Raster Placement
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
Present raster analog systems for CRT character displays require an initial adjustment to set the raster position on a cathode ray tube (CRT). Once this adjustment is made, the operator is not able to change its position. It would be desirable for the operator to be able to position the raster in a more comfortable or convenient position on the CRT than where it was set by the factory. There are three methods of placing the raster image on a CRT. The first is to modify the top margin reference voltage via a digital-to-analog (D/A) converter or other suitable device. The value could be set via the keyboard with a program function (PF) key. For example, upon actuation of the PF key, the raster would increment down from the top of the screen. An example is seen in [*].