[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

This report studies the relationship between the transmission characteristics and the eye-pattern in NTSC system of Teletext. The computer analysis is adopted to this study by using the method of the eye-pattern simulation. In this report, the eye-height is evaluated by the value of the sampling clock point linked with the clock-run-in signal.
The results indicate that the eye-height is more dependent on the group delay characteristics than on the amplitude characteristics, and the optimum bit-rate is effected by the group delay characteristics of the lower side of the pass-band, for example, in case of 5.7 Mb/s bitr-ate, the tolerance of the group delay characteristics of lower side needs to be set within ±100 ns.
In conclusion, an improvement of the group delay characteristics both on the transmitter and the receiver is one of the key factors for better quality of Teletext System.

View full abstract

A liquid crystal display device using depolarization in a twisted nematic layer (DTN-LCD) has advantages in wide viewing angle and sharp threshold, so that it is suitable for a large scale matrix display. Therefore, the design conditions of this DTN-LCD for applying to video display were investigated, and according to the conditions, a matrix LCD-panel with 120×160 picture elements was made as a trial. When the LCD-panel was driven by an amplitude selection method of 1/60 duty ratio, the contrast ratio was about 1 : 5.5, the response time was 90-250 ms and the viewing angle was larger than ±40°.

View full abstract