Matsushita Electric Industrial Co., Ltd.

Nippon Hoso' Kyokai

Panasonic Corporation

Katsumi Morita

Mitsuo Isobe

Masanori Hamada

Yuichi Ninomiya

Masayoshi Abe

Teruhiko Izumi

Seiichi Gohshi

The dropout detection circuit of the invention includes: a high-speed envelope detection circuit for detecting an envelope of a reflection signal of a light beam with a first time constant; a low-speed envelope detection circuit for detecting an envelope of the reflection signal with a second time constant larger than the first time constant; a differential circuit for generating a difference signal indicating the difference between the envelopes detected by the envelope detection circuits; and a comparator for converting the difference signal to a binary value according to a predetermined binary criterion. The high-speed envelope detection circuit makes the first time constant larger during recording than during reproduction, to enable stable dropout detection irrespective of during reproduction or during recording.

Dropout detection circuit and optical disc apparatus

A subsample signal processing apparatus includes a wide-band D/A converter receiving a digital television signal which is compressed in band by subsampling. A signal processor subjects a video signal portion of an output signal from the D/A converter to wide-band processing. The signal processor subjects a sync signal portion of the output signal from the D/A converter to narrow-band processing. An output terminal of the signal processor and an input terminal of a subsequent A/D converter are coupled with wide-band coupling characteristics.

Subsample television signal processing apparatus

A picture signal processing apparatus of a TV set, which has a picture signal memory/processing circuit to which picture signals are inputted. This picture signal memory/processing circuit includes a frame memory and has two alternative functions. One of the functions is to apply LPF processing in a temporal domain to a high frequency signal component, and the other function is to take out and output a still picture signal from the picture signal.

Picture signal processing apparatus having a temporal filter and a

A television receiver is provided with two field memories for storing movement control signals, an OR circuit, a frame memory for storing the present and previous fields, a pair of switches controlled by a freeze signal, a switch controlled by the output signal of the OR circuit, and another switch for changing over its output signal to and from the output signal from the switch controlled by the OR circuit and the signal from the frame memory representing the present field. One frame's worth of video signals of the present field and the previous field are stored in the frame memory by a freeze signal. The signals stored in the frame memory provide a freeze picture having no multi-line dimness by virtue of using the present field and the previous field for the still picture image portion and the present field for the moving picture image portions of the present field and the previous field.

Television receiver

An image signal processing apparatus is provided which is applicable to a motion adaptive Y/C separation of an NTSC signal and a time-domain/spatial interpolation of a high definition television signal band-compressed by sub-Nyquist sub-sampling. The apparatus includes a still image processing circuit having frame memories, a motion image processing circuit having a line memory, a mixing circuit for mixing outputs of these processing circuits, a circuit for detecting image motion of an input image signal and applying a resultant control signal to the mixing circuit, and a signal mode control circuit for selectively adapting the image processing circuits for the processing of the NTSC signal or the high definition television signal. The motion detecting circuit includes a narrow band detecting circuit for producing a one-frame interval difference signal of a signal spectrum of a pure low frequency component from the NTSC signal or the high definition television signal respectively, a wide band detecting circuit for a two-frame interval difference signal and a composition circuit for composing outputs of these detecting circuits. The still image processing circuit, motion image processing circuit and mixing circuit are adapted to operate for the Y/C separation with the NTSC signal and for the interpolation of the high definition television signal, respectively.

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Suita, Japan

Katsumi Morita