Developments in the Pal colour-television system: a unified system of tolerances

A very brief historical introduction is followed by a philosophical discussion of tolerancing methods. Two methods of quality control are discussed; one based upon Norbert Wiener´s ideas concerning interpolation, extrapolation and smoothing of stationary time series, and the other based upon industrial sampling theory. The latter concept is elaborated into a possible method of obtaining advanced warning of the departure of the properties of the television signal from the desired values. A final Section repeats some earlier proposals for the appropriate subdivision of overall tolerances into component tolerances to be applied to the different parts of the complete television transmission chain.