A Magnetic Disc Video-Scan Converter

Magnetic disc memories that store information at video bandwidths require auxiliary devices to record and play back single or multiple frames of video data. By choice of modulation technique new information may be added at slow or rapid rates to a video frame which is continually repeated at normal TV scan rates for the benefit of an observer. As an example, a video x-y plotter is described. Disc scan conversion has freedom from image fading, relatively multiframe capacity and ability to erase and record data selectively and rapidly. Minimum registration errors and good shading characteristics allow special forms of visual data manipulation. Integration characteristics differ from those of the scan-conversion tube. There are various modulation methods as well as various applications in monochrome and color. Expedients for achieving high resolution are outlined and an economical slow-scan TV system for general communications use is described.