Hitachi, Ltd.

Hidehiko Sawamura

Yoshizumi Eto

Masuo Umemoto

Hirotake Ishii

A method and an apparatus for digital signal recording and/or reproduction are disclosed in which tracks are formed sequentially on a recording medium by use of a head unit mounted on a rotary cylinder, an input digital data is recorded in the recording medium, and the digital data thus recorded is reproduced. The input digital data is modulated into a code word having at least d (d: an integer of at least two) successive bits of high- and low-level data in a signal waveform recorded in the recording medium. The timebase of the code word is compressed. The compressed code word is recorded in the tracks of the recording medium by use of the head unit. The code word recorded and compressed in the recording medium is reproduced. The timebase of the reproduced code word is expanded, and the input digital data is reproduced from the expanded code word.

Method and apparatus for digital signal recording and/or reproduction

A replay equalization circuit for reproducing digital image information recorded on a recording medium includes a transducer for reading the digital image information, an equalization circuit connected to the transducer for equalizing an output of the transducer based on a speed information input, a clock recovery circuit connected to the equalization circuit for extracting a clock signal from an output of the equalization circuit for latching the output of the equalization circuit in response to the clock signal.

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Hachioji, Japan

Hidehiko Sawamura