Abstract: A tape drive which may accommodate tapes having a servo control track thereon as well as tapes without such tracks advantageously uses a lockout to prevent unwanted head translation when operating in an open loop mode. The lockout may be accomplished by energizing a voice coil motor to fix the head position, driving the voice coil motor to a fixed stop positioning the head, or latching a rocker connected to the head, thereby preventing movement of the head. The latching/unlatching function may be accomplished by driving an actuator supporting the beam springs, head and latch to an end-of-track position to similarly unlatch the rocker and return the assembly to a servo controlled mode of operation.

Abstract: The present invention provides a movable magnetic head unit including a signal transmission element. The movable magnetic head is mounted upon a rotary drum of a drum assembly which also includes a stationary drum, the rotary and stationary drums being supported by a shaft. The signal transmission element transmits a control signal wirelessly to the rotary drum to drive an electromechanical transducing element which moves the magnetic head. The signal transmission element may include rotary transformers, mounted on the rotary and stationary drums, facing each other. In a further embodiment, the signal transmission element may include an optical transmitter for optically transmitting the position control signal to an optical receiver mounted on the rotary drum. Wireless transmission of the position control signal prevents noises from appearing on a display, enables stable compensation of deviations of the magnetic head and improves reliability of the magnetic head unit.

Abstract: A magnetic recording and reproducing apparatus includes a rotary drum that has a magnetic tape wound around the drum and first and second magnetic heads mounted on the drum for scanning the magnetic tape as the tape is advanced to reproduce an information signal recorded in successive oblique tracks on the tape. The first magnetic head has a magnetic gap that is inclined in a clockwise direction, relative to a line that is normal to a scanning direction of the magnetic heads, when viewed from the rotary drum. The second magnetic head has a magnetic gap that is inclined in a counterclockwise direction, relative to a line that is normal to the scanning direction of the magnetic heads, when viewed from the rotary drum. A tracking control circuit controls the scanning locus of the first magnetic head relative to an oblique track which the first magnetic head reproduces.

Abstract: A method and apparatus for testing for mechanical defects in a disc drive during manufacturing test is disclosed. The disc drive performs a special test seek to a destination track involving maximum acceleration and deceleration current to induce resonant frequencies in an actuator servo position error (SPE) signal. During track following on the destination track, the SPE is filtered by a sample and accumulate operation, resulting in the detection and characterization of the resonant frequency. The characteristics of the detected and characterized resonant frequency are compared to predetermined maximum acceptable threshold values, and when the characteristics exceed the threshold values an error flag is set, indicating a failure condition for the disc drive, enabling the disc drive to be removed from test for subsequent remedial actions.

Abstract: A disk drive for operating in an environment in which the drive is subject to physical shock includes a circuit which senses movement of a transducer head support arm which result from a shock's rotational component. The rotational shock is detected as a residual BEMF signal in the drive's VCM coil winding. The residual signal is extracted from much larger position control signals that are applied to the VCM winding during normal system operation by providing circuits that simulate the VCM winding voltage caused by the position control signal and subtracting the outputs of the simulation circuits from the actual VCM coil winding voltage. This eliminates the normal operating components and leaves a residual signal that represents only the small portion of the VCM BEMF signal that results from the rotational shock. A threshold circuit compares the shock BEMF signal to a predetermined threshold. If the BEMF signal exceeds the threshold, disk drive write operations are aborted.

Abstract: Apparatus and method for recording digital video and audio data on a record medium receives digital video and audio data and topic data having identifying topics, and generates menu data in accordance with those identifying topics. The video and audio data, topic data and menu data are recorded on a record medium in the form of a coded signal having the recording format comprised of respective video, audio and subcode areas in which the video data, the audio data and the menu data, respectively, are provided. The video and audio areas have respective auxiliary areas in which the topic data is provided. In addition, auxiliary character data is generated when character information is received by a teletext broadcast system and recorded in the auxiliary areas of the video and audio areas of each track.

Abstract: A method and an apparatus for recording and reproducing data on disk recording medium, capable of effectively reducing the unnecessary vibration of the spindle motor and the noises associated with it, and improving the tracking characteristic of a head with respect to the vibration of the spindle motor. The apparatus includes a head for recording and producing data with respect to a disk recording medium; a rotational driving mechanism including a spindle motor for driving the disk recording medium in rotation according to a driving waveform; and a waveform correction unit for detecting a vibration of the rotational driving mechanism and correcting the driving waveform supplied to the rotational driving mechanism according to the detected vibration.

Abstract: A method and apparatus are provided for maintaining file readback performance compensating for readback errors caused by head/disk interaction used with a data detection channel in a direct access storage device. A readback signal is sensed from at least one disk surface and a data channel error rate is detected responsive to the readback signal. The detected data channel error rate is compared with a first predetermined threshold value and a gain of a phase lock loop (PLL) in the peak data detection channel is optimized responsive to an identified data channel error rate with a first predetermined threshold value. The PLL gain is adjusted until a lowest error rate is detected. A failure warning for the direct access storage device is provided to a user when the detected PLL gain is greater than a predefined loop gain value.

Abstract: A motor speed control device includes a frequency signal generating circuit for generating a frequency signal proportional to a rotation frequency of a motor, a frequency measuring circuit for measuring a frequency of the frequency signal, a speed error signal extracting circuit for extracting a speed error signal by operation comparing the frequency of the frequency signal with a predetermined control target period, a filter circuit for eliminating rotation frequency components of the motor contained in the frequency signal or the speed error signal and harmonic components thereof to output another speed error signal, and a speed error signal feedback circuit for feeding-back negatively the other speed error signal from the filter circuit to the motor, in which owing to the fact that the filter circuit has predetermined transfer functions, it suppresses non-uniform components contained in the speed error signal and the phase error signal due to the frequency signal (DFG signal) proportional to the rotation s

Abstract: A digital storage system is disclosed in which a flying read/write head is loaded onto the surface of moving storage media with controlled velocity to avoid contact with the surface of the storage media. Head load velocity is detected by measuring the back EMF generated by the head arm actuator. Improved control and accuracy is obtained by breaking up the head arm actuator drive power into a series of pulses and measuring the back EMF induced into the low impedance voice coil of the head arm actuator in between pulses but only after the actuator current has been reduced to substantially zero in order to avoid interference by actuator current induced voltages.

Abstract: The present invention relates to a method and apparatus for writing servo tracks of a magnetic disk unit, and has an object of providing a servo track writing method and apparatus which can reduce a mechanical vibration of a head in the steady state and can shorten a settling time of the system. A detecting face is set in the vicinity of a head arm end portion 22 of a magnetic disk unit 2, and a capacitance probe 28 is provided as a gap detecting means for detecting a gap in a head moving direction between the detecting face and the head arm end portion 22. Further provided are a rotary positioner 26 as a positioning means for moving the capacitance probe 28 in the head moving direction to position it at a target position, and a head drive system control means for moving a head 14 of the magnetic disk unit 2 so that the gap is kept constant, to position the head 14 at a predetermined servo track writing position.

Abstract: A synchronization technique is described which finds use in a disk array subsystem comprising a plurality of disk storage devices connected to a controller. In response to signals from each of the devices specifying their angular position at a particular time, the controller calculates the relative angular positions of the devices and issues a signal to each of the devices specifying the amount and direction of change in rotational velocity required to achieve synchronization. In a two device subsystem, the signal to one device will specify a speed decrease and the signal to the second device will specify a speed increase.

Abstract: A tracking control apparatus includes a memory for storing tracking control information of a previous track corresponding to a present position of a current track being tracking-controlled, and a tracking controller for generating a new tracking control signal by using a tracking error signal derived from the current track and stored tracking control information for the previous track, to thereby enhance the precision of tracking control of the present track even when the track is deformed. A corresponding method is also described.

Abstract: Servo track pair position and longitudinal tape position is determined for a tape using dedicated servo format. The tape includes at least one set of data tracks and dedicated servo tracks wherein adjacent servo tracks are defined by longitudinal lines through the edges of erased or non-recorded tape portions. The information about servo track pair numbers and/or servo sample numbers is recorded into portions of the tape and is decoded and read back together with signals from the servo track. The information is recorded in a digital manner by using a digital block format of data blocks requiring less bytes per block than a data block provided on the data tracks. If information about longitudinal tape position is not required, information may be recorded in an analog manner using a fixed set of predetermined frequencies.

Abstract: A data recording disk drive includes acceleration rate sensing for controlling or modifying one or more disk drive operations in response to external shock or vibration. An acceleration rate sensor is mounted on the disk drive housing and provides direct detection of acceleration rate of the disk drive when subjected to external shock or vibration. The sensor includes two spaced-apart piezoelectric transducers that operate in current mode. The transducers are connected to an interface circuit that generates two voltage signals that are directly proportional to the angular and linear acceleration rates, respectively, when the disk drive is subjected to an external force. The disk drive microcontroller uses the voltage signals to inhibit writing of data or modify the servo control signal to maintain the heads on track during track seeking or following.

Abstract: This invention provides a small-sized and easy-assembling head positioning apparatus having a coarse moving mechanism and fine moving mechanism, by which the desired fine moving accuracy is easy to attain. A head positioning apparatus has a first stepping motor, a lead screw, and a cylindrical rack for coarse moving. The cylindrical rack is formed by rotating a rack around the axis of the lead screw and is provided with the lead screw. The head positioning apparatus has a second stepping motor and gears for reducing the speed of the rotation of the second stepping motor for fine moving means, and fine moving is carried out by moving the cylindrical rack by the gear. The lead screw is provided so that the first stepping motor could be moved in a X1, X2 direction in the fixed moving range.

Abstract: A recording head Hw1 records a record signal including a data region, a pilot signal region, and a mask region with a width of 3 Tp. A recording head Hw2 overwrites the record region of the head Hw1 with another data. Since the recorded signal includes the mask region, the pilot signal region recorded by the head Hw1 is not erased. The recording head Hw1 overwrites with a record signal. At this point, since the recorded signal contains a mask region, the former pilot signal region is not erased. Instead, a new pilot signal region is formed. By repeating these operations, pilot signal regions are adjacently formed at track edges of a track corresponding to the recording head Hw1. Since the pilot signal is reproduced by a reproducing head with the same azimuth as the recording head, the pilot signal with a short wavelength can be used.

Abstract: In a magnetic head drive for a magnetic tape recorder of a helical scan system, a pair of first and second longitudinal bimorph elements fixed to a support member is connected to a flexible bridge member and a magnetic head is mounted to the bridge member. A pair of first and second electric sources supply electric voltages independently to electrodes of the first and second bimorph elements. The voltages applied to the bimorphs are controlled against a deviation from a record track in a magnetic tape to keep a protrusion quantity of the magnetic head constant for automatic tracking. In a magnetic tape recorder wherein the upper and lower drums of a rotating head scanner are fixed and the magnetic head is rotated along an elliptical orbit, the two bimorphs are controlled not only against a deviation from a record track in a magnetic tape but also to a rotation angle of the magnetic head in order to keep a protrusion quantity of the magnetic head constant.

Abstract: In a magnetic recording/playback apparatus for recording and playing back a digital video signal on a helical track of a magnetic tape using two or more rotary heads, the playback image at the time of high-speed playback is improved by setting the tape travel speed at the time of high-speed playback at an even multiple of a normal playback speed. Further a tracking phase is offset by one half the track pitch with respect to the tracking during normal speed playback. Alternatively, essential information of the information having been high-efficiency coded is recorded in the central part, and near the ends of the tracks, while high-precision information is recorded in intermediate parts intermediate between the central part and the parts near the ends. Still alternatively, the video data of one of the consecutive fields is recorded in the central part of the tracks and the video data of the other of the consecutive fields is recorded near the ends of the tracks.

Abstract: This invention relates to a caption signal recording and reproducing control device of a video cassette recorder which can record and reproduce those caption signals recorded on a tape and transmitted from a broadcasting station, selectively.