Channel-Compatible 6-MHz HDTV Distribution Systems

A TV distribution system is described whose purpose is to achieve the highest possible image quality within a prescribed analog channel bandwidth, assumed here to be 6 MHz, using receiver technology deemed to be practical in the near future. This system is designed to be used immediately for controlled-access systems such as cable. It is also suitable for eventual broadcasting use in a two-stage strategy in which an intermediate backward-compatible system is the first stage. Applications to fm, recording, and digital transmission are described. — The efficiency of analog channel utilization is improved over NTSC by using double sideband quadrature modulation of two 3-MHz signals on a single carrier in the center of the band, and by elimination of the retrace intervals and sound carrier. Higher perceived quality for a given transmission rate is achieved by dividing the signal into components according to both spatial and temporal frequency, and transmitting the appropriate combination of components according to the degree of motion in each scene. A “smart,” programmable, open-architecture receiver is proposed capable of decoding a wide variety of signal formats and displaying the image at higher line and frame rates than transmitted. Such a receiver can also display the backward-compatible EDTV system described in a companion paper, and can be upgraded over time by virtue of its programmability and by adding hardware and software modules.

Published

1988-01

Content type

Original Research

DOI

10.5594/M00532

ISBN

978-1-61482-917-1