Abstract: A magnetic recording disk drive has a rectifier circuit made up of bipolar transistors. Upon removal of power to the spindle motor, the rectifier circuit converts AC spindle motor output to DC actuator coil current to drive the actuator to a parking ramp where the read/write heads are "unloaded" from their respective disk surfaces. The transistor emitter-base junctions are connected to a switch, such as a pair of field-effect transistors, that is responsive to removal of power to the spindle motor. The total current flowing in these emitter-base junctions is small due to the use of series resistors and because the current in the emitter-base circuit does not flow through the actuator coil. The emitter-collector paths of the bipolar transistors are connected as a three-phase, full-wave rectifier to the actuator coil.

Abstract: A pick-up device for optical recording and playback includes two linear actuators coupled to an optical module and lying in a plane normal to the surface of an optical recording medium. The actuators are obliquely inclined to the optical axis of the optical module. Proportional differential actuation of the linear actuators moves the optical module bi-axially, i.e., normal or parallel to the recording medium surface, permitting control of both focus and tracking of information bits on the surface. The preferred embodiment employs two bi-directional linear actuators, each comprising a pair of back-to-back uni-directional actuators, each of which includes a flexible tubular housing enclosing a stack of thin, perforated disc-shaped electrodes separated by a dielectric fluid. Conductive elastomeric spacer rods support the disks in a parallel, longitudinally, spaced apart arrangement.

Abstract: A method and an apparatus for optimizing movement of a disk drive's head actuator arm away from a magnetic latch that holds the arm in a parked position at the Inner Diameter (ID) of a disk. Current energizing of the arm's actuator motor moves the arm away from the magnetic latch and is controlled to compensate for any change in magnetic holding force. When the disk drive is powered up, a current pulse of one polarity is applied to the actuator motor. This initial current pulse normally moves the arm away from the magnetic latch and is followed by a current pulse of the opposite polarity to decelerate movement of the arm. If this initial sequence fails to move the arm away from the magnetic latch, the magnitude of the two current pulses is increased, and the opposite polarity pulse is followed by a small magnitude current of the one polarity. The read signal from the head is monitored to indicate that the arm has moved into the disk's central databand area, and then into the disk's Outer Diameter (OD) area.

Abstract: In a magnetic recording system, an asymmetry detector reverses the phase of a read, single-frequency test signal to indicate to a micro-controller whether recording signal asymmetry is present. Upon detecting such asymmetry, the micro-controller causes a current source coupled to the recording head to adjust a write current to correct the timing of a written data signal.

Abstract: A technique for writing a servo-pattern on a storage medium located in a recording device having an internal recording head. A timing pattern is generated on the storage medium with the internal recording head and a radial positioning value is determined in order to radially position the internal recording head. The servo-pattern is written using the internal recording head at locations determined by the timing pattern and the radial positioning value.

Abstract: A device for switching a read head from a write mode to a read mode includes a voltage ramp generating circuit, generating and outputting a voltage ramp after a write operation; a variable current source for discharging an initial current of the read head, wherein a current output by the current source is controlled proportionally to the slope between the beginning of the voltage ramp and a first threshold of the ramp, the current source having an initial maximum value higher than the initial current of the head; and an accentuating circuit for accentuating the ramp slope between the beginning of the ramp and a time when the current output by the variable current source becomes equal to the initial current present in the head.

Abstract: A track following positioning system including filtered average servo demodulators for maintaining the position of a magnetic tape head in alignment with tracks of data stored in magnetic medium. A servo head tracks a centerline in a servo written region of the magnetic medium and generates servo head signals corresponding to the displacement of the servo head from the centerline. A filtered average servo demodulator detects the servo head signals and generates servo error signals for realigning the tape head with respect to the magnetic medium in response thereto. To generate servo error signals, the filtered average servo demodulator peak detects and averages the rectified and filtered output signals and then subtracts a proportion of the peak detected signals from the average detected signals.

Abstract: An automatic deck adjusting apparatus having a tape running system adjusting mechanism for adjusting a VCR deck automatically and control means for controlling the adjusting mechanism to adjust the tape running system automatically. The tape running system adjusting mechanism comprises a plurality of screw driver tip assemblies for screwing adjustment screws and/or nuts in the system, a motor assembly for rotating the screw driver tip assemblies by a predetermined angle, a driver housing for fixedly supporting the screw driver tip assembly and the motor assembly in place, moving means attached to the driver housing for reciprocating the housing, a positioning means aligning the deck mechanism and the screw driver housing to be coincided in position with each other when they are coupled together and, a video camera for monitoring the position of the tape passing through guide posts and an audio/control head assembly or head drum.

Abstract: In an information recording/reproducing apparatus, a recording/reproducing head is moved across tracks on a recording medium by a linear motor which is controlled to effect a seek operation of the head to a target track. A CPU for controlling the apparatus judges the seek direction of the head and whether the seek distance of the head is equal to or greater than a predetermined distance, in conformity with a recording or reproduction command from a host controller on the basis of a logical address designated by the host controller and a logical address at which the head is positioned. When the seek distance is equal to or greater than the predetermined distance, the linear motor is activated in the seek direction. Then, the logical address designated by the host controller is converted into a physical address and a control is effected such that the head reaches the target track.

Abstract: An information recording and reproducing apparatus includes an encoding circuit for encoding information codes and for adding redundant codes to the information codes to form error detection and/or correction codes, a recording and reproducing head for recording and reproducing the information codes and the redundant codes on and from the recording medium and a decoding circuit for detecting and/or correcting errors in reproduced information codes by using the redundant codes. The apparatus has an output terminal for externally outputting the information codes partially processed through the decoding circuit and only a part of the redundant codes.

Abstract: A high speed dubbing apparatus for producing magnetic tapes such as video, audio or computer soft tapes, is provided. Typical form of the apparatus may comprise 2 master tape playback devices for synchronously playing back 2 divided master tapes respectively recorded with 2 divided master signals obtained by dividing time-divisionally an original master signal having an original data sequence by 2 and for outputting the 2 divided master signals, a double speed recording signal producing device for time-compressing each of the 2 divided master signals to 1/2 to obtain a double speed recording signal from the 2 divided master signals while restoring the original data sequence in the double speed recording signal and a recording device for recording the double speed recording signal on a slave tape running at a speed which is twice the nominal playback speed of the slave tape.

Abstract: An optical pickup device for an optical disk includes a semiconductor laser, an optical waveguide for propagating the laser beam, at output grating coupler for focusing the propagated beam through the optical waveguide onto one point of a optical disk, an input grating coupler for coupling a beam reflected and diffracted from the optical disk into the optical waveguide and for dividing the beam to detect focus and tracking error signals, and photodiodes for detecting the beam coupled into the optical waveguide by the input grating coupler. The photodiodes include a 3-piece-divided photodiode for detecting readout signals and focus error signals, and a 2-piece-divided photodiode for detecting tracking error signals. The optical waveguide, output grating coupler, input grating coupler, and the photodiodes are integrated on the surface of a slab substrate, allowing the optical pickup to be miniaturized and made light, and thus allowing the access time to be faster.

Abstract: A magnetic recording and reproducing apparatus capable of recording video, audio and other information on a magnetic tape by, for example, the helical scanning method. A rotary head is rotated at an m-fold speed to record intermittent tracks on the magnetic tape so that real-time simultaneous monitoring is performed. By high-speed dubbing due to high-density intermittent recording and by increasing the number of repetition of track scanning, the information is recorded and reproduced simultaneously with a plurality of channels. Any tracking error is detected to form a continuous and uniform track pattern. With this intermittent comb-shaped recording, reciprocating recording and reproducing can be realized.

Abstract: A digital signal source and an analog signal source, such as might be contained in a video tape cassette, can be discriminated from each other in a video tape recorder by providing only a minimum of electrical contacts. A first contact is connected to a voltage source and a fourth contact is connected to ground, while second and third contacts are connected through resistors to the voltage source. The second and third contacts are respectively connected through fixed contacts of two change-over switches to a serial data line and to a serial clock line of a data processing circuit, and those contacts are also respectively connected through the other fixed contacts of the change-over switches to comparing input terminals of a group of comparators.

Abstract: It is an object of the invention to realize a DTF control in a wide frequency range and a noiseless high-speed replay at several tens of times the normal relay speed without degradation of picture quality. It is also an object to provide an optimum contact between the head and the tape at all times by performing the tension control with high precision and in wide frequency range.A pair of supply side stationary pins 10a.sub.1, 10a.sub.2 and a supply side movable pin 9a driven by a supply side tape actuator 11a are provided on the magnetic tape supply side of the head cylinder that has a rotary head H. By controlling the supply side tape actuator 11a to move the movable pin 9a, the tension of the magnetic tape T at the head cylinder can be controlled. When the tape is replayed at speed different from the recording speed, the supply side tape actuator 11a and a takeup side tape actuator are operated differentially from each other to perform a good tracking.

Abstract: A magnetic disk apparatus including a head disk assembly, a servo control circuit, a head positioning microprocessor, a sector pulse generating circuit, a head selection circuit, and a main controller. The head selection circuit selects any one of disk media in a data read/write operation. The servo control circuit controls an operation of a head positioning motor. The head positioning microprocessor controls an operation of the servo control circuit based on an external command. The sector pulse generating circuit has a plurality of sector counters for counting a clock signal and generating sector pulses having different periods, selects one of the sector pulses from the sector counters based on an input selection signal, and outputs the selected sector pulse always with a predetermined separation or longer.

Abstract: A single deck dual tape path videocassette recorder/playback system enabling near simultaneous multiple functions with respect to a broadcast or cable communicated television signal. The system consists of standard elements which allow the receipt of a videocassette, the extracting and return of video tape from and to the videocassette, and the recording of a broadcast or cable communicated signal. The system also consists of two tape path assemblies and a videotape compartment consisting of a tape feed channel, a storage assembly, and a vacuum system. All elements are included within a single housing utilizing a common power supply, tuner, controls, and switching and control circuitry enabling simultaneous multiple functions using both tape paths, as well as additional function selections.

Abstract: A visual search control of digital video files capable of realizing a high quality image even in the fast forward and fast reverse modes, while facilitating a quick mode switching among the normal playback mode and the fast forward and fast reverse modes.

Abstract: A tape transport system control device for controlling a tape transport system in which a tape payed out from a supply-side reel driven by a supply-side reel motor travels through a predetermined path to be taken up on a takeup-side reel driven by a takeup-side reel motor, includes a tape speed control servoloop for the takeup-side reel motor, a tape tension control servoloop for the supply-side reel motor, a detecting part arranged to detect a difference between a tape tension obtained on the side of the supply-side reel and a tape tension obtained on the side of the takeup-side reel, and a loop arranged to feed the detected difference of tension forward to the supply-side reel motor.

Abstract: An editing apparatus is for use with a tape-form recording medium in which a tracking pilot signal and several synchronizing blocks each of which contains a synchronizing signal, a synchronizing signal number and a recording mode data are multiplex-recorded into a first recording area of each track which has a plurality of recording areas. Using the synchronizing signal and the synchronizing signal number, a pilot sampling signal for determining the timing of sampling the pilot signal and an editing timing signal for determining the recording location in a desired recording area following the first recording area are produced. Using the recording mode data, the discrimination of the current recording mode is carried out. After the tracking control is executed through sampling the tracking pilot signals from adjacent tracks at timing of the pilot sampling signal, a data signal is recorded into the desired recording area after the first recording area according to the editing timing signal.