CHARACTERISTICS OF MEASUREMENTS IN HIGH-DEFINITION TELEVISION

High-definition television (HDTV) technology is in the stage of formation today. Measurement of HDTV signal parameters when the signals are formed and transmitted is a new problem, whose solution should precede development and manufacture of HDTV hardware. The purpose of measurement is derivation of quantitative and qualitative estimates of the physical process properties that yield specific characteristics of formation, conversion, distribution, and reproduction of HDTV programs; this, first of all, is associated with broadbandedness of signals used and with allowance for special features of the effect of their various distortions on the quality of reproduced images. A frequency band of approximately 30 MHz (up to 60 MHz in the case of progressive scanning) is assigned to the brightness components when forming HDTV signals, and approximately 15 MHz to different colors signals. The requirements imposed on the precision with which these signals are formed and transmitted before being coded and thereafter are substantially increased, since signal distortions are more noticeable when observing images on wide-format screens. Clearly, the physical causes for the occurrence of HDTV signal distortions, as is the case in conventional television, are associated with inertia, static and dynamic nonlinearities of the means for their formation and transmission, as well as with appearance of additive and multiplicative interferences of various kinds. The authors of this paper propose initial data for designing methods for measuring HDTV signal parameters in the course of signal formation and transmission. We recall that, tests are currently under way in the USSR involving various types of experimental HDTV hardware proposed by a number of countries. The purpose of these investigations is selection of a single world HDTV standard.