A Practical Narrow-Band Television System: Sampledot

A new narrow-band TV system called Sampledot, which produces a live picture with motion and sharpness that is a satisfactory replica of conventional TV, is described. Bandwidth compression ratios of 10:1 have been demonstrated with relatively simple electronics. Higher compression ratios are projected using the technique with a dynamic display memory or storage. The system is compatible with NTSC or EIA video cameras and monitors. Sampledot works on the principle of gating the line-scan video signal raster with a pseudorandom (PR) dot-sample matrix. About 3 percent, or less, of the picture is sent every fast scan field instead of the usual 50 percent. At the receiving end, the monitor raster is gated in step with the PR matrix. The natural integration effects of the eye-brain characteristics plus optional display memory, the large redundancy of TV video, and the high degree of correlation between adjacent TV pixels are exploited in the Sampledot technique.