Analysis of Hue Jitter by Quadrature Modulation of Picture Carrier

Abstract

A new TV system which transmits signals multiplexed by the quadrature modulation of a picture carrier is under development. Since hue jitter is caused by the quadrature modulation, there is the previously reported problem of compatibility with NTSC. In this paper, an analysis of the production mechanism of the hue jitter is presented. Hue jitter becomes more pronounced as the ratio of multiplexed signal level to picture carrier level modulated by luminance signal gets higher and as the frequency of the multiplexed signal gets lower. Hue jitter is reduced by narrowing the band width of the carrier reduction circuit in a TV set using syncronous detection. Based on this analysis, hue jitter reduction methods decreasing the multiplexed signal level and decreasing the lower frequency area of a multiplexed signal are proposed.