Pseudo-Random Dot Scan Television Systems

The principal psychophysical requirements of the human eye are satisfied by a television frame frequency of about 1 or 2 c/s. To avoid flicker with such low-frame rates, a random dot scan is employed in conjunction with long-persistence phosphors. Experiments show that 15 per cent dot flicker is tolerable. Ten systems are discussed, including a two-million-element picture with 4-Mc/s bandwidth; tape recording at 15 in/s; continuous relaying of satellite pictures; short-wave transmission; phonevision; and very low-frame rate applications that use a scan conversion tube.