Hitachi, Ltd.

Toshiro Aizawa

Shigemitsu Higuchi

Atsuo Suga

Kouji Fujita

Minoru Kosuge

Michio Masuda

Atsushi Yoshioka

Katsuyuki Watanabe

Tomomitsu Kuroyanagi

Hiromasa Fujii

Yuji Inaba

A helical scan data recording and playback apparatus includes a tape driving motor which continuously transports a magnetic tape on which there are a data recording area and a plurality of reference helical tracks preceding the data recording area. The data recording area is for recording and playback of target data on and from data recording tracks in the data recording area. The reference helical tracks have a specific pattern prerecorded thereon in a predetermined area of the helical reference tracks, and a configuration of the helical reference tracks is similar to a configuration of the data recording tracks. The apparatus further includes a rotary head cylinder, at least one magnetic head, coupled to the rotary head cylinder, which scans tracks on the magnetic tape and plays back the specific pattern from the reference helical tracks on the magnetic tape before recording or playback of target data on or from the data recording tracks in the data recording area on the magnetic tape, and a servo circuit which controls the tape driving motor based on the specific pattern played back from the reference helical tracks.

Helical scan data recording and playback method and apparatus wherein

Recording areas for tracking on which specific servo patterns are recorded are provided preceding data tracks on which data is to be recorded on a recording tape scanned by a helical scan system. The data tracks and recording areas for tracking are recorded at different azimuths. At the time of a playback operation, etc., the specific patterns in the recording areas for tracking are played back by the helical scan system and tracking is performed by using the playback timing.

Data recording and playback apparatus using a helical scan system with

A recording and playback apparatus for recording and playing back onto and from a magnetic tape and utilizable with a memory card adapted to be mounted onto the apparatus. The memory card is adapted to at least one of store operational characteristics for the apparatus to enable automatic setting of the operational characteristics of the apparatus when mounted and, if the apparatus includes a self-diagnostic information unit, the memory card enables storage of at least self-diagnostic information generated upon occurrence of a trouble during operation of the apparatus. The stored self-diagnostic information enables analyzing of the cause of a cause of the trouble occurring during operation of the apparatus at a time subsequent to the occurrence and taking of countermeasures with respect thereto. If the memory card is not mounted or is in a nonwritable state, the apparatus is provided with a storage device for storing the self-diagnostic information. The memory card also enables storage of other information relating to the apparatus.

Recording and playbackk apparatus

A magnetic tape drive in a helical scan system can shorten retry operation time. A data signal reproduced from magnetic tape through reproducing heads is supplied to a regenerative signal processing circuit. If an uncorrectable error is contained in the signal, the regenerative signal processing circuit outputs error information to a system controller. Then, the system controller sends a retry instruction to a movable head controller. When receiving the retry instruction, the movable head controller supplies movable head control signals to displacement elements which then displace the reproducing heads along a rotating shaft of a rotary drum for re-scanning an error occurrence data track. This retry operation is repeated until no error is detected. The magnetic tape is run at lower speed or is stopped as required during the repetitive retry operation.

Magnetic tape drive with displaceable head capable of a re-try operation

A data recording and reproducing apparatus of a helical scanning system includes a unit for recording and reproducing an information signal in an oblique information track on a magnetic tape by a rotary magnetic head and a unit for recording and reproducing a control signal on the magnetic tape in a longitudinal direction thereof. Further, the data recording and reproducing apparatus includes a memory unit for storing a difference (X-value error information) between a predetermined X value and a distance (X value) between a record starting position of the information track and a recorded position of the control signal, a unit for recording X-value error information on the magnetic tape individually each time information is recorded, a unit for reproducing X-value error information on the magnetic tape, and a unit for shifting a reproduced phase of the control signal in accordance with the X-value error information.

Data recording and reproducing apparatus

Data recording and playback apparatus using helical scan system with

For the purpose of data compression and expansion in the playback mode reproducing data including video data and audio data recorded on a magnetic tape, a relative speed signal is generated from a circuit on the basis of the moving speed of the magnetic tape and the rotation speed of a head drum, and the characteristic of the recorded data is controlled according to this relative speed signal. The tension of the magnetic tape is detected by a circuit, and the phase difference between the detected tape tension signal and a reel rotation speed command signal is detected by a circuit so as to control the tape tension according to the detected phase difference. When a target value of the drum rotation speed is changed, a drum drive signal is changed stepwise at a predetermined time interval, and the amount of delay of a drum rotation reference signal delayed according to a signal indicative of the rotation speed of a capstan is changed, so as to determine the range in which both the capstan rotation speed and the drum rotation speed can be changed. Interfaces are disposed between a system controller and a pitch controller so as to control the tone pitch of the audio signal according to the capstan rotation speed signal.

Digital video signal reproducing apparatus with compression and

A luminance and chrominance signal separation circuit for use in a video tape recorder wherein in the recording mode a three-line comb filter is made to be an adaptive type comb filter for separating a luminance signal from a chrominance signal and in the playback mode the comb filter is made to eliminate residual chrominance signal components in the luminance signal. Switching circuits are provided in the invention to permit the switching of the luminance and chrominance signal separation circuit between recording and playback modes and noise reduction is accomplished by a feedback line correlation circuit.

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Ebina, Japan

Toshiro Aizawa