Television picture signal generators: an evolutionary cycle

It is not uncommon to find that the application of solutions to particular problems has to be delayed until the existing technology has advanced to a stage beyond that currently known. The progress in the science of television picture signal generation can be traced through this evolutionary cycle, commencing with proposals embodying an all-mechanical system of scanning, followed by proposals embodying a mixture of mechanical and electronic scanning, until an all-electronic system was finally adopted for television purposes. However, as progress has been made in the development of short-decay-time phosphors, multi-stage photomultipliers and high-intensity light sources, various proposals for television systems have been made which include a reversal to the earlier forms of mechanical scanning. The impetus of this work can possibly influence other parts of the television system and might ultimately lead to alternative types of display in the television receiver.