Nippon Hoso' Kyokai

Matsushita Electric Industrial Co., Ltd.

Fuji Photo Film Company, Limited

Katsuya Yokoyama

Hironobu Katayama

Shozo Nakagawa

Tatsuji Kitamoto

Tatsushi Bannai

Seishi Sasaki

Shigeru Awamoto

Takuji Sekiguchi

Hiromichi Shibaya

A unidirectional traveling-surface-wave by ultrasonic oscillation is generated on a surface of an oscillator, and a magnetic tape is run in the direction opposite to the traveling direction of the surface wave by pressing the surface of the oscillator against a surface of the magnetic tape.

Method of and system for driving magnetic tape

Disclosed is a video signal recording system, in which the input video signal is rid of unneeded portions, transformed on the time axis and divided into n channels so that they are recorded in a bandwidth narrower than 1/n of original one. The system also enhances the latitude in choosing a clock frequency for time-axis conversion and a track width, thereby optimizing the picture quality and recording time length on a trade-off basis.

Video signal recording method and associated recording/reproducing

In a helical-scan magnetic record/playback system, n magnetic heads (where n is an integer greater than one) are disposed close to the outer wall of a head drum, spaced from one another by 2.pi./n radians with respect to the rotational axis of the head drum and also spaced from one another by approximately 1/n of the width of a magnetic tape in the axial direction of the head drum. The magnetic tape is wound around the head drum over an angle of 2.pi./n radians or more with respect to the rotational axis of the drum. With the rotation of the head drum, a video signal is time-sequentially divided for recording on n tracks of the tape and for reproduction therefrom. The invention results in reduced friction between the tape and the drum, thereby providing smooth travel and easy loading of the tape. According to this invention, a still or slow-motion picture can be reproduced without an external memory and the reciprocal travel of the tape.

PCM helical-scan magnetic record/playback systems

In a digital magnetic recording and reproducing apparatus, a digital code signal to be recorded is given a code conversion by means of modulo-2-adding another digital signal thereto to prevent a continuation of the same binary signal levels for a prolonged period. The signal level of the reproduced digital code signal is corrected by level comparison with a threshold level provided by applying the above reproduced digital code signal to a compensator and peak rectifiers, which have the same time-constant, and then the reproduced digital code signal is given another code conversion by means of modulo-2-adding still another digital signal provided for restoring the code conversion, so that it is possible to reproduce the original digital code signal faithfully.

Digital magnetic recording and reproducing apparatus

Growing community of inventors

Machida, Japan

Katsuya Yokoyama