Abstract: An optical information recording medium and a method of mastering an optical information recording medium. Cross-talk is avoided even when phase pits flanking a groove are radially aligned so that preformat information can be reliably reproduced after information is recorded at the grooves. A phase pit that encodes preformat information for a groove is radially spaced from that groove by a partition wall but is connected to an adjacent groove. When mastering, respective first and second exposing light beams are used to form the grooves and the phase pits, and the spacing between the two beams and, therefore, the width of the partition walls in the radial direction is precisely and easily controlled by controlling the inclination angle of at least one of the beams relative to an objective lens in the mastering exposure system.

Abstract: The invention concerns a method for optical recording of data on a photosensitive storage medium, characterized in that the data are encoded according to different possible states for the various components of a non-linear susceptibility tensor of the photosensitive medium and it consists in irradiating simultaneously at least a point of said support with write beams whereof the polarization is controlled for optical recording of a given non-linear susceptibility tensor on the photosensitive medium.

Abstract: A technique for generating sector pulses in a hard disk drive using hardware involves: receiving read reference clocks produced during a read operation of the hard disk drive and producing a byte clock in sync with every byte; outputting the byte clock as an effective production clock in a time interval in which no servo gate signal indicative of a servo zone on a magnetic disk or the hard disk drive is produced, counting the production clocks, and comparing the counted value obtained during the production clock counting step with a previously stored value indicative of a sector length and generating a sector pulse when the counted value is equal to the previously stored value.

Abstract: A system for performing insertion editing on the audio portion of an audio-visual signal; wherein the video portion of the signal is coded in field/frame units, and the audio portion of the signal is coded in block units which are not synchronized with the field/frame units. The system allows the block units of audio to be insertion edited according to a command that is synchronized with the field/frame units of video--despite the non-synchronous relationship between the block and field/frame units. Audio editing is implemented through a switching scheme that adjusts the audio insertion begin point and end point to account for differences between the block unit and field/frame unit boundaries.

Abstract: The present invention is a system for reading information stored on a plurality of disk surfaces. The system comprises a plurality of channels each containing a preamplifier having first and second terminals for connection to an MR head. A bias circuit is provided common to all of the plurality of channels. The preamplifier in each channel includes first and second channel select circuits responsive to first and second channel select signals and current output from the bias circuit to output currents based on the current's output from the bias circuit. The preamplifier in each channel also includes first and second complementary output transistor circuits responsive to the current's output from the first and second channel select circuits and to the first and second voltages to provide bias current through the respective MR head connected between the first and second terminals of the respective channel. The system is entirely symmetrical around ground for improved common mode rejection.

Abstract: A method and apparatus for transferring data in a disc apparatus are disclosed which perform on-the-fly correction. The disc apparatus includes a disc drive for transferring read data to a disc controller after a head has read the data from a storage disc. This disc controller transfers the data from the disc drive to a host device. The data transferring method reads data recorded on the storage disc in a CKD format in which one block is composed of a plurality of subblocks each having an error correction code. Errors in the data are detected by use of an error detection code on a subblock-unit; and after correcting the data of the error-detected subblock, the corrected data on the subblock-unit are transferred with the data of at least the previous subblock, at a speed higher than a reading speed.

Abstract: A head positioning control system applied to a magnetic disk unit in which a positioning operation is carded out with reference to a history of past positioning errors stored in memory. A control unit determines whether or not the head is on-track by comparing past position error signals stored in memory to current position signals. The target position is compensated according to the past position error when the target position is designated.

Abstract: In a head displacement measuring method, prior to actual data recording or data reproduction, either one of the recording head and the reproducing head is wobbled, and the test data is recorded in the disk-shaped recording medium by the recording head. Then, the test data is reproduced from the test data by the reproducing head, and displacement between the recording head and the reproducing head is detected on the basis of the reproduced test data. Thus, the displacement may be detected more easily with higher precision than with the conventional optical detecting method.

Abstract: A method for setting an information reader to a target information recorded position on an information recording medium in an information reproducing apparatus includes steps of reading a start position from the medium by the reader, which contacts the medium, separating the reader from the medium after reading the current position, driving the medium after separating the reader from the medium, successively estimating a current read position based on the start position and a driving motion during the driving step, checking whether the estimated current read position matches a target position, contacting the reader with the medium and reading position information when the estimated current read position matches the target position, comparing the position represented by the read position information with the target position and driving the medium, contacting the reader, while reading the position information when a mismatch is detected, and comparing the position represented by the newly read position informat

Abstract: An apparatus and process are disclosed for automatically changing the speed of a recording tape from a first speed to a second speed, based on a one-time determination of predicted time of changeover. The second speed is 1/n of the first speed, where n is any real number greater than 1. A central processing unit determines the time of changeover at the start of the recording process, using inputs from a recording timer and a reel detector to determine the program time and the remaining tape time on a supply reel. When the program time initially exceeds the remaining tape time at the first speed, the system automatically predicts and then implements the changeover to the second speed, such that the first speed portion is maximized to take advantage of its superior signal-to-noise ratio.

Abstract: In a synchronous read channel for magnetic recording, a timing recovery phase-locked loop (PLL) comprises a technique for smoothing a timing gradient .DELTA.t computed from estimated sample values and actual sample values. If an estimated sample value for computing the timing gradient is zero, then the timing gradient is increased, and if all of the estimated sample values for computing the timing gradient are zero, then the timing gradient is copied from its prior value. Smoothing the timing gradient reduces gain variations in the PLL and results in more effective timing recovery.

Abstract: A magnetic recording/reproduction apparatus comprises a magnetic tape running apparatus to rotate a rotary drum and run a magnetic tape with the magnetic tape being in contact with, at least, part of the circumferential surface of the rotary drum, a plurality of erasing magnetic heads installed on the rotary drum so that the magnetic tape are in contact with the heads and used to erase recording signal, a plurality of recording magnetic heads used for recording, a plurality of erasing circuits installed on the rotary drum to output erasing signal to each of the erasing magnetic heads, a plurality of recording circuits connected to the recording magnetic heads respectively and installed on the rotary drum so that the recording circuits are selectively be gone to active state and non-active state, one or more rotary transformers connected to erasing circuits in common, and a driving circuit to record information signal in the magnetic tape through recording magnetic heads, recording circuits, and rotary transfo

Abstract: An apparatus and method have been conceived for using a digital audio tape (DAT) in an audio logger for the purposes of storing and retrieving audio data. This is accomplished in a manner such that the data is received and recorded in a time related manner. Provision is made for accommodating the transfer drive rate of the DAT through use of a buffer between the signal processor of the logger and the DAT. In addition, the method of storing the data results in greater use of the available space on the DAT as the DAT tape only writes for those periods when audio is present on a channel.

Abstract: An optical disk apparatus includes a photodetector divided into eight segments which receive the laser beam reflected from the optical disk and produce signals based on the laser beam sport thereon. In this apparatus, these eight segments are combined in several patterns for the recorded information reproduction, the tracking error detection, and the focus error detection, respectively. For the recorded information reproduction, eight segments are used as combined in three segment cells RC1, RC2, and RC3 which extend in a direction parallel to each other such that the segment cell RC1 is in center and is sandwitched by other segment cell RC2 and RC3. The segment cells RC1, RC2, and RC3 are located perpendicular to the recording track of the optical disk and produce three signals C, R, and L indicative of the laser beam intensity of the laser beam spot thereon, respectively. Thus obtained signals C is multiplied by a constant K and then added to the other signals R and L.

Abstract: An information recording-reproducing apparatus in which the seeking operation of an information recording/reproducing head is effected while controlling the velocity of the head. The head is moved by a linear motor in a direction to traverse the tracks provided on a recording medium. During the movement of the head, a tracking error signal is generated and is detected. The moving velocity of the head is detected at every predetermined period. The linear motor is controlled in synchronization with the velocity detection so that the head moves in conformity with a predetermined target velocity on the basis of the detected moving velocity.

Abstract: The present invention senses angular acceleration of a Head Disk Assembly ("HDA") in a disk drive servo system and provides an acceleration feedback signal. A filter network filters the acceleration feedback signal and supplies a filtered signal for nullifying tracking error caused by shock, vibration and windup disturbances to the system.

Abstract: The present invention achieves improved disk response performance by optimizing the placement of the disk sectors associated with the directory and File Allocation Tables (FATs) on the drive. The physical sectors associated with the directory are located approximately on the middle track of the disk and the FAT sectors are relocated adjacent to the track groups the FAT sectors serve. This novel placement of sectors effectively reduces the disk head seek time and effectively reduces the rotational latency compared to the prior art.

Abstract: An active filter characteristic changeover circuit, for use in a video cassette recorder, includes an active filter, for a video signal, whose passing band width is dependent on a control current value, a current supply circuit for supplying a control current to the active filter, and a changeover circuit for changing over the control current value outputted from the current supply circuit between in a VHS mode and in an SVHS mode.

Abstract: An apparatus for recording and reproducing an encoded video signal from a source encoder comprises a decoder for performing a decoding process for the encoded video signal to produce a decoded video signal, an encoder block for compressing the decoded video signal using a spatial correlation to produce an intra mode compression signal, a buffer memory for storing the intra mode compression signal, a mode controller for generating a clock pulse used to read out data in the buffer memory in accordance with a longer playing time recording and a normal playing time recording and a recording and reproducing unit for recording and reproducing the intra mode compression signal read from the buffer memory.

Abstract: A video signal recording apparatus has a high band signal recording circuit for deeply recording onto a recording medium a high band component of a video signal separated from a composite video signal and a low band signal recording circuit for recording on a recording medium a low band component of a signal separated from the composite video signal using a much shallower recording depth.