Hitachi, Ltd.

Yuji Inaba

Hideo Nishijima

Shigemitsu Higuchi

Kaneyuki Okamoto

Kouji Fujita

Atsuo Suga

Toshiro Aizawa

Tomohide Sorihashi

Yoshiaki Umehara

Kooji Kaniwa

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

The specification discloses a magnetic recording signal reproducing apparatus for controlling a magnetic tape and reproducing magnetic heads. In the magnetic recording signal reproducing apparatus of the invention, a magnetic tape which is moved for magnetic heads attached to a rotary cylinder is traced by the magnetic heads and signals recorded on tracks of the magnetic tape are reproduced. A construction of the apparatus includes a tracking control system, a tape tension control system, and an apparatus for selectively switching operations of both of the control systems. The tracking control system includes: an apparatus, attached to the rotary cylinder, for moving the magnetic heads in the width direction of the tracks in accordance with a tracking signal; and an apparatus for sampling the signals detected by the magnetic heads, for comparing a preceding sampled value with a present sampled value, and for generating the tracking signal such that the present sampled value is larger than the preceding sampled value. The tape tension control system includes: an apparatus for detecting changes per predetermined time in levels of the signals detected by the magnetic head; an apparatus for giving a tension to the moving magnetic tape and for adjusting the tension in accordance with a tension control signal; and an apparatus for generating the tension control signal to adjust the tension according to change amounts per predetermined time of the signal levels to a reference value. Further, the switching apparatus includes switching means for receiving the signals detected by the magnetic heads and for selectively energizing either one of the tracking control system and the tape tension control system in accordance with the levels of the signals. Another magnetic recording signal reproducing apparatus according to the invention comprises: two magnetic heads arranged to a cylinder so as to simultaneously trace adjacent tracks; an apparatus, attached to the cylinder, for individually moving the two magnetic heads in the width direction of the tracks in accordance with a head position control signal; and an apparatus for generating the head position control signal to move the magnetic heads in the width direction of the tracks in a manner such that when the recorded signals are reproduced at a speed different from a tape moving speed upon recording, amplitude levels of the reproduction signals detected by the two magnetic heads locating at predetermined track positions have a relation of opposite phases.

Magnetic recording signal reproducing apparatus

A cassette tape-loading apparatus applied to a magnetic recording and reproducing apparatus using a cassette tape comprises a device for determining the amount of rotation of supply and take-up reels, a device for detecting the rotational direction of the reels, and a device for detecting the amount of tape drawn out of the cassette. Before loading the cassette tape, the ratio of winding diameter between the supply and take-up reels is computed, and the result is used to set the torque of the reel-driving motors and start the loading operation. At the time of loading, on the other hand, the amount of rotation of the two reels is determined, and the winding diameters of the reels computed from the winding diameter ratio and the amount of drawn-out tape thereby to set a proper tension of the magnetic tape. Since the tension applied to the magnetic tape and the torques of the reel motors are set in accordance with the winding diameter ratio and the winding diameters, magnetic tape of substantially equal amount is drawn out of each of the two reels, with the result that the magnetic tape is not subjected to an abnormal tension, thereby making possible a stable cassette tape-loading operation without damaging the tape or displacing the tape position.

Cassette tape-loading apparatus

A tape transport control apparatus relating to changing means of high speed reel control transport and low speed capstan control transport in a tape transport control of a magnetic recording regenerative apparatus or the like. Particularly in a period of transition from the high speed driving state to the low speed driving state, a capstan motor is controlled through means for comparing phase of the control signal of the tape transport speed regenerated on the tape with phase of the capstan frequency generator signal of the capstan, and after the phase comparing means detects that the tape speed and the capstan rotational speed are coincident, the pinch roller is pressed against the capstan.

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Katsuta, Japan

Yuji Inaba