This paper describes the noise characteristics of letterbox EDTV, using a three dimensional weighting function. This function is useful in the evaluation of television systems using temporal-spatial processing. By evaluating the weighted noise power, it is shown that the weighted noise power of letterbox EDTV becomes larger than that of the conventional television system because of the effect of displaying on a large screen and the noise from the additional helper signal.
The viewing conditions of the television at home have not been investigated more than twenty years in spite of development of display technology. The purpose of this paper is to clarify the average viewing conditions at home compared to ITU-R Recommendation 500. A survey about the viewing conditions was made through questionnaires. About 200 answers were examined and additional measurement was carried out to know the illuminance of inactive tube screen and peak luminance. The result shows that the average ratio of viewing distance to picture height is 5.7H and the ratio of luminance of inactive tube screen to peak luminance satisfies the condition described in Rec.500.
The Broadcasting Technology Association (BTA) has been elaborating specifications of the television programs timer recording system by Japanese teletext since 1991. BTA made a rule "BTA T-003" in July, 1993. These specifications aim at detemining the presentation form and the transmission method of television programs in the system for television programs timer recording by Japanese teletext. These specifications shall be applied to teletext programs, the presentation form, the transmission method and receivers with built-in teletext.
NHK has been studying for ISDB(Integrated Services Digital Broadcasting) since 1985 A number of television programs are able to transmit through ISDB By transmitting the additional data related to the programs, extended television services can be realized for television audiences One of the extended services is a program guide for program selection. In accordance with examples of existing program guide in NHK television programs and newspapers, necessary functions for the program guide and transmission data capacity in the extended television service are discussed in this paper.
Trellis-Coded 8PSK Modulation (TCM) is an atractive modulation schem for digital television signal transmission because TCM has coding gain of 3dB over QPSK without losing spectrum efficiency. We have built a TCM modem for a data rate of 60Mbps in order to confirm its practical perfomance in satellite transmission. The modem can be used for both TCM and DQPSK. This paper describes performance of TCM over Gaussian noise channel and over non-linear channel, and compares it with DQPSK.
This paper analyzed the perfomance of the hierarchical modulation scheme for 20 GHZ digital HDTV broadcasting satellite system in the presence of the rain fall attenuation. And this paper clarified an optimum power assignment ratio to maximize the spectrum efficiency. The paper also clarified an another optimum power assignment ratio to maximize the signal-to-noise power ratio.