Sony Corporation

Takashi Chikuma

Ichiro Tsutsui

In a television receiver having a picture tube with the picture plane aspect ratio being different from the image size aspect ratio in the existing standard television system, when an image in the existing standard television system is displayed, variation in the video signal positioned adjacent to at least one of the vertical ends on the picture plane of the picture tube is detected. If no variation an enlargement mode enlarging the image size is selected, and if any variation a normal mode displaying the image in ordinary size is selected, thereby the enlargement mode or the normal mode is selected automatically in response to the effective image size and the troublesome work of manually changing the modes is eliminated.

Apparatus for controlling display of an image on a large aspect ratio

A blanking circuit for use in a television receiver designed for video signals of both the HDTV and double-speed scanning NTSC systems comprises a sawtooth generator, a reference voltage generator, a comparator for comparing the sawtooth signal with the reference voltage, a switch for selectively changing the relative level of the reference voltage and the sawtooth signal in conformity with the input broadcasting system, and with the output of the comparator supplied as a blanking pulse to a video signal processor. Due to selective change of the time constant of the sawtooth generator or the change of the threshold level of the reference voltage, a proper blanking pulse can be produced with high precision to prevent losing the image on the monitor CRT screen, and an adequate blanking interval is exactly obtained.

Growing community of inventors

Kanagawa, Japan

Takashi Chikuma