A simplified theory of shuffling [HDTV applications]

Shuffling is a standard technique used in compatible high-definition television systems where, in connection with subsampling, it permits the halving of the number of lines, e.g. from a 1250/2:1/50 format to a 625/2:1/50 format. The authors analyze the process in detail considering only the first quincunx field of the four subsampled fields (the two-dimensional model). First, the two-dimensional shuffling operation is formulated in an appropriate signal theory framework. An equivalent model for shuffling is then derived: it consists of two vertical filters and one horizontal modulator, which is useful for shuffling frequency-domain analysis. As an example of shuffling theory application, spectral analysis of the shuffling error in MAC compatible systems is carried out