| 摘要 |
Digital data is transferred from a video screen, such as from the CRT screen of a television receiver, into a micro-computer, by modulating a small area of the screen on successive television field scans. On each field scan, a plurality of data bits are modulated respectively onto a plurality of adjacent lines within the area. Thus, e.g. one or two (Fig 3) complete bytes can be transferred on each field scan. The data may be detected on the CRT screen by a light-pen device. In a further embodiment (Fig 2) many data channels may be transmitted by modulating several areas simultaneously. Each area may comprise either complete or partial horizontal line scans. <IMAGE> |
