An HDTV encoder design for the transmission of PALplus signals, supplement with a digital residual component

This paper discusses the design of a video encoder which will enable PALplus compatible HDTV transmission, by embedding a digital residual component within the standard analogue PALplus television signal. The design strategy includes a 2-D diagonal prefilter, together with a QMF band-splitting filter pair, from which the residual is initially derived. The performance of these filters is reviewed, especially in respect of the errors introduced by aliasing and crosstalk distortion. A number of different digital modulation techniques are then examined for the transmission of the residual signal and a qualitative appraisal of their effectiveness presented