Abstract

With the planned conversion of studio equipment to digital component signal operation, there will be a requirement for high quality PAL decoders at the interface with current equipment. The addition of movement detection circuits to picture delay comb filters was expected to produce a decoder with good overall performance. However, movement detection methods have so far been unable to produce a satisfactory mode switching signal for the adaptive control. If this problem proves fundamental, an alternative non-adaptive approach will be needed in which the bandwidths of the luminance and chrominance output signals may have to be noticeably reduced. In this case, the positioning of decoders to minimise the number of decode and recode operations will be an important factor in maintaining reasonable quality from PAL signals during the changeover period to YUV.