Hitachi, Ltd.

Hitachi Heating Appliances Co., Ltd.

Katunobu Takeda

Yukio Fukui

Yoshio Miura

Junichi Ikoma

Keizo Shimizu

Tokinori Furuichi

Ikuo Yuki

Nobuaki Naoi

Masao Oguri

A noise reduction circuit comprising: a high-pass filter for extracting the high-frequency component of an image signal; a coring circuit for extracting a faint signal component included in the extracted high-frequency component as noise; a low-pass filter for extracting the low-frequency component of the image signal; an adder for adding the cored high-frequency component and the low-frequency component extracted by the low-pass filter; and a coring control circuit which detects the level of a luminance signal and controls the coring range of the coring circuit according to the level of the luminance signal. Since noise is visually more conspicuous in a dark portion of a picture than in a bright portion of a picture, the coring control circuit increases the coring range when the level of the luminance signal is low, namely, for a dark portion of a picture, and decreases the coring range when the level of the luminance signal is high, namely, for a bright portion of a picture to make noise indistinct over the entire area of a picture plane.

Dynamic noise reduction circuit for image luminance signal

A skip/arm servo system for a video disc player comprises a device adapted to skip a signal sensing element, such as a stylus for detection of information recorded on a disc, in a direction crossing a recording track, a stylus position detector adapted to detect the relative position of the stylus to a cartridge movably mounting the stylus, a comparator comparing the detected relative position with a reference relative position to produce an error output, a cartridge driver responsive to the error output to move the cartridge so as to maintain the stylus in the reference relative position. A setting device is adapted to variably set the reference relative position in accordance with a reproduction mode selected by the operator, whereby a special mode reproduction can readily be accomplished or the stylus can be readily released from a locked groove in the disc.

Skip/arm servo system for a video disc player

A high frequency heating apparatus is provided with a hood so constructed as to limit infrared ray energy reaching an infrared ray detecting element for detecting infrared rays radiated from an object to be heated within a heating chamber. In heating apparatus, the influence by the reflection of infrared rays is minimized by making the absorption factor approach to about '1' with blackening the inner surface of the hood. Also, the rotation of a chopper to detect infrared rays radiated from the object through chopping operation is detected by a mechanical switch. The output signal from the infrared ray detecting element is synchronous-rectified in synchronism with the switching operation of the mechanical switch.

Microwave oven

An inverter circuit comprises a reactor and a capacitor connected in series to a load to supply the load with a series resonance high-frequency power, a secondary winding provided at the reactor, and means for feeding a voltage generated in the secondary winding back to a power supply through switching means of a thyristor. The switching means is made conductive to feed the voltage generated in the secondary winding back to the power supply when supply voltage detecting means detects that a supply voltage exceeds a predetermined voltage.

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Yokohama, Japan

Katunobu Takeda