An analog display system for digital graph plot output

Abstract

Two versions of an analog display program have been assembled for the analog display of digitally derived graph plot information. Input to the analog display system is the magnetic tape output by the "DRAW" subroutine used at the U.S. Naval Postgraduate School Computer Facility. The fast version of the program, driving an oscilloscope as the display element, provides a clear and accurate display of the graph points, but is of limited usefulness due to the small size of the standard scope face and the flicker in the presentation. The slow version, employing an x-y plotter as the display element, also yields an adequate display, and at a slightly faster rate than the existing digital plotter currently used by the Computer Facility for graphical output. A linear interpolation routine has been implemented in the slow version, so that plotter response is not affected by coarseness in the data points.