Victor Company of Japan, Limited

Susumu Saito

Isao Owaki

Yasuhiko Fujii

Shinji Nakamura

Takaro Mori

Masami Yamazaki

A magnetic tape is simultaneously recorded with digital signals on one or a plurality of forward recording tracks and reverse recording tracks thereon as the tape travels in a predetermined direction. The digital signals are reproduced from the forward recording tracks when the tape travels in a direction from one end to another end thereof, and the digital signals are reproduced from the reverse recording tracks when the tape travels in a direction from the other end to the one end thereof. The digital signals are recorded with the phase of the digital signals which are recorded on the forward or reverse recording tracks, relatively advanced with respect to the phase of the digital signals which are recorded on the reverse or forward recording tracks, so that solitary reproduced waveforms which are reproduced from the forward and reverse recording tracks respectively have substantially the same assymmetry of zeros or the same symmetry of zeros. The first recording tracks are scanned upon reproduction in a direction opposite to the predetermined direction in which the tape traveled upon recording, and the second recording tracks are scanned upon reproduction in a direction which is the same as the predetermined direction in which the tape traveled upon recording.

Magnetic tape having multiple tracks and recording apparatus therefor

A data recording and reproducing apparatus promotes error-free and speedy exchange of data between separate recording media. When desired primary data is to be recorded on a master recording medium, secondary data is added to the primary data in order to detect and correct data errors. The primary and secondary data are recorded on the master recording medium in a plurality of series which differ in recording sequence from each other. The primary data is reproduced from the master recording medium together with the secondary data for the different series at the same time, regardless of their recording sequences. The reproduced primary data is allowed for error check and correction based on the secondary data and is recorded in the slave recording medium.

Digital data duplication apparatus

A method and apparatus for digital magnetic recording of data in which digital data is recorded on a magnetic recording medium after being demodulated by the NRZI (Non-Return-to-Zero Inverted) system and read thereoutof timed to magnetic flux reversal caused by the recorded data on the recording medium. The digital data is encoded in a predetermined manner before the NRZI modulation so that at least part of 'false' bits contained in the digital data is converted into 'true' bits, resulting in an increase in the number of 'true' bits. The encoded data is written into the recording medium after the NRZI modulation. In the event of reproduction of the data from the recording medium, self-clocking occurs to generate a data readout timing. The increased number of 'true' bits insures desirable self-clocking. The data read from the recording medium is decoded to the original digital data.

Digital data transmission system with modified NRZI

A digital signal of data and synchronization words is distributed to a plurality of circuit paths and transformed into non-return-to-zero inverted (NRZI) signals for application to a plurality of stationary parallel magnetic heads for recording the distributed NRZI signals along first parallel tracks on a magnetic tape when driven toward one end thereof and along second parallel tracks interleaved with the first tracks when the tape is driven toward the other end thereof. Each of the transducers has a differential characteristic with which the recorded signal is detected as a ternary signal, the detected signal is converted to a binary signal to recover the original digital signal. The synchronization word is detected from the recovered digital signal to generate a timing signal indicative of the position of each binary digit of the data word with respect to the detected synchronization word. In response to the timing control signal the timing of each binary digit derived from each transducer is aligned with those derived from the other transducers and arranged into a series of successive data words for conversion to an analog signal.

Multi-track digital recording and playback system

A digital signal having a configuration of blocks or frames is recorded via a multi-track record on a first group of tracks, such as odd tracks, of a master tape which is driven at a first direction. Then when recording another digital signal by forming a second group of tracks, such as even tracks, in a second direction which is opposite to the first direction, the digital signal prerecorded on the first group of tracks is derived to produce a speed signal indicative of the tape speed at which the digital signal was recorded on the first group. The speed signal is then compared with a reference signal having a predetermined frequency for producing a control signal, which is used to control the driving speed of the master tape. Thus the second group of tracks is formed with the running speed of the master tape being controlled. As a result, the phase difference between the first and second groups of tracks is constant throughout the entire length of the master tape. The speed signal may be derived from a synchronous signal recorded on a control track, which may be formed when forming the first group of tracks.

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Sagamihara, Japan

Susumu Saito