Sony Corporation

Masato Sekine

Norio Shoji

Mitsuru Sato

Masayuki Katakura

Tetsuya Iizuka

Tokuya Fukuda

Katsuhisa Daio

Junkichi Sugita

Kimimasa Senba

Kiyoshi Furuya

A nonlinearity compensation circuit is disclosed which includes an inverse hyperbolic function generation circuit for converting differential currents corresponding to input signals in&plus; and in&minus; into differential voltages which increase in proportion to an inverse hyperbolic function, an offset provision circuit for providing an offset corresponding to control signals c&plus; and c&minus; to the differential voltages outputted from the inverse hyperbolic function generation circuit and a hyperbolic function generation circuit for converting the differential voltages to which the offset has been provided by the offset provision circuit into signals which increase in proportion to a hyperbolic function and outputting the resulting signals as output signals out&plus; and out&minus;. Consequently, compensation for the nonlinearity such as second order distortion can be performed for the read signal from a recording medium.

Nonlinearity compensation circuit and method, control circuit and method for nonlinearity compenstation circuit and recording and/or playback apparatus employing the same

An automatic gain control circuit having a variable gain amplifier circuit, a signal level detecting circuit connected to the variable gain amplifier circuit for generating a detect signal the level of which changes in response to a signal level of an output signal of the variable gain amplifier circuit, and a gain control circuit for controlling the gain of the variable gain amplifier circuit in accordance with the signal level of the detect signal, and the gain control circuit having a differential amplifier circuit having first and second input terminals, the first and second input terminals being connected to the signal level detecting circuit for receiving the detect signal, a first reference voltage source connected to the first input terminal of the differential amplifier so that a first predetermined voltage is provided instead of the signal level of the detect signal in response to the signal level of the detect signal and a second reference voltage source connected to the second input terminal of the differential amplifier for providing a second predetermined voltage.

Automatic gain control circuit

Apparatus for recording audio and video signals comprises a signal processor for producing a processed video signal and a frequency-modulated audio signal. The frequency-modulated audio signal is obtained by frequency-modulating a carrier in response to an input audio signal. A magnetic recorder records both the frequency-modulated audio signal and the processed video signal in oblique tracks arranged successively on a magnetic tape. The recording is done selectively in a first recording mode wherein the oblique tracks are formed with spaces between successive tracks or a second recording mode wherein successive tracks are contiguous. A modulation control controls the frequency-modulation carried out by the signal processor to produce the frequency-modulated audio signal with a first modulation index in the first recording mode and with a second modulation index greater than the first modulation index in the second recording mode.

Apparatus employing adjustable modulation index for reducing cross talk

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Kanagawa, Japan

Masato Sekine