Matsushita Electric Industrial Co., Ltd.

Nobuyoshi Yokobori

Yoshiaki Igarashi

Hiroshi Okamoto

Tetsuo Maeda

Masashi Urayama

Hiroyuki Iitsuka

Toshio Inaji

Kazutsugu Kobayashi

Keiichi Kameda

A combined memory medium is constructed by an optical disc used as a read-only memory, a cartridge for holding or receiving the optical disc, and a fixed memory which is held in the cartridge. The read or write operation for the fixed memory is carried out by structure different from that used for the optical disc so that the optical disc and the fixed memory constitute an integral memory medium. A combined memory medium drive apparatus includes the combined memory medium, a disc access block for reading out the data on the optical disc, a memory access block for performing reading or writing of data for the fixed memory, and a control block for interpreting an instruction sent from an external device to control the reading of data from the optical disc through the disc access block and the reading or writing of data for the fixed memory through the memory access block, in which the optical disc and the fixed memory are complementarily used. A combined memory medium playback apparatus includes the combined memory medium drive apparatus and a processing block for controlling it to process the data output therefrom, thereby being capable of performing writing. Because the control program is stored in the fixed memory, the drive apparatus and the playback apparatus are able to be operated with the combined memory medium alone, dispensing with the need for another memory medium.

Combined memory medium, drive apparatus and method therefor and playback

A rotary head deflection apparatus for allowing magnetic heads to properly scan signal tracks recorded on a magnetic tape, and used for a helical scan system video tape recorder, which is constituted of driving coils wound onto a stator and movable members carrying magnetic heads and magnets, so that the driving coils are energized to enable the magnetic heads to be displaced in the direction of the axis of rotation of the rotary member.

Rotary head deflection apparatus

An output circuit to drive a current into a load. Collector voltage of a current controlling transistor is automatically adjusted to maintain h.sub.FE of the transistor constant, whereby saturation of the transistor and excessive power consumption are avoided. A brushless motor using the output circuit. Current detectors detect emitter current and base current of output transistors and h.sub.FE of the transistors are kept constant, whereby excessive torque loss and harmful vibration are avoided. A limiter limits excessive torque control to prevent power transistor saturation. A switching mode power supply adjusts the collector voltage of the transistor in a feedback loop to keep h.sub.FE constant.

Output circuit and brushless motor using the same

A phase control circuit for improving the stability after a predictable rotational speed change of a rotating apparatus and a magnetic reproducing apparatus for performing slow motion reproduction by means of intermittent tape transport and yet being free from transverse swings of the reproduced picture comprises a phase shift circuit which shifts the phase of the reference signal, which is produced by dividing a source signal, at a desired rate, to maintain the phase locked at the very moment during which the rotational speed change is changing. The relative speed of the magnetic head rotation is kept constant during the intermittent tape movement under the condition of the phase being locked.

Phase control circuit and magnetic reproducing apparatus using the same

A differential output circuit for generating a bipolar DC current for an armature winding without requiring a bipolar power source. A combination of transistors and resistors are utilized to effectively apply a bipolar driving current. The use of only transistors and resistors in the differential output circuit enables its easy implementation as an integrated circuit.

Differential output circuit

A device for intermittently driving a magnetic tape has a capstan for driving the magnetic tape, a motor directly connected to the capstan for driving the capstan, a tachometer for detecting the rotating speed of the motor and producing an output, and a speed control having a settable speed controller for setting a desired motor speed and into which the output from the tachometer is fed back for enabling the speed control to sense when the motor is rotating at the desired motor speed. An intermittent drive control is provided for supplying a triggering signal to trigger said settable speed controller to cause the settable speed controller to operate the speed control for accelerating the motor to the desired motor speed and driving it at that speed, the intermittent drive control supplying the triggering signal in response to a speed setting signal and a head switch signal. A detector for detecting a control signal recorded on the magnetic tape while the motor is being driven at the desired speed is connected to the intermittent drive control. The intermittent drive control is further responsive to the detection of the control signal for discontinuing the triggering signal after the passage of a predetermined period of time for causing the settable speed controller to decelerate the driving of the motor from the desired motor speed, whereby the position of the magnetic tape relative to the position of the recorded control signal at the end of the deceleration by the speed control is constant.

Device for driving magnetic tape

A drive system for a brushless dc motor to control the magnitude of the torque of a motor which has permanent magnet rotor and Hall generators. Multipliers determine the magnitude of current to each phase armature winding so as to determine the current sharing rate among the armature windings according to the rotation angle of the rotor, whereby degrading of torque uniformity due to variation of Hall generator characteristics is avoided. Each multiplier multiplies 2 signals, one being the output of the Hall generator, the other being the difference between the torque control input and the fed back signal of total armature current. Also a torque direction input is supplied to each multiplier to determine the direction of the rotational torque.

Growing community of inventors

Osaka, Japan

Nobuyoshi Yokobori