Conversion of a PAL Colour-Television Signal into a Symmetrical Dot-sequential Signal

An N.T.S.C.-type colour-television signal can be converted into a driving signal for a one-gun display tube without full demodulation of the sub-carrier signal. With the adoption of the PAL system for colourtelevisionbroadcasts in many countries of Europe the question arises whether similar methods can be devised for transcoding a PAL signal into a driving signal for dot-sequential display systems. The analysis of this problem leads to the conclusion that a slight modification of the PALswitching axis or a slight modification of the composition of the luminance signal is desirable. Practical conversion methods are discussed and some experiments are described. Employment of the standard PAL signal instead of the modified signal introduces small errors which are hardly observable. It is concluded that conversion of the PAL chrominance signal into a driving signal for one-gun display systems is well within the possibilities and does not require complex circuitry