Abstract: Apparatus for detecting data track misregistration is described. The present invention involves the interaction of a microprocessor with a demodulator. Microcode within the microprocessor initiates a misregistration scan of all data tracks at specific intervals to generate a calibration offset table that is used to direct the heads during the subsequent interval. A demodulator obtains the peak values of calibration servo bursts, displaced one-half of the track width to either side of a track, and outputs a timing pulse proportional to their respective peak voltage values. A timer within the microprocessor extracts the time values, and the misregistration displacement is calculated by the comparison of the inner burst and outer burst time values. The calculated displacement is used in the offset table for subsequent disk references.

Abstract: A digital servo control system for a disk drive provides asynchronous servo information signal demodulation. The system includes a digital demodulator having a digital squarer that removes any phase component of the digitized servo information signal and includes a burst signal accumulator that accumulates the squared terms according to respective burst timing intervals to produce a digital, quadrature position error signal (PES). The demodulator also can include a filter comprising a harmonic notch filter preferably implemented as a Hilbert Transform filter. Alternatively, the demodulator does not include a filter and squarer and, instead, the squarer comprises a sum-and-squarer that sums the squares of odd and even digitized samples. A split burst servo pattern for the servo control system is comprised of half-width transitions that can be written in a single pass of a recording head and therefore has no phase misalignment between adjacent flux patterns.

Abstract: A servo control system provides adaptive compensation for a variety of tracking and seek problems found in disk drives. The servo control system is ideally implemented in digital form for accuracy, speed and compactness. A first embodiment includes two modes, a tracking (or position) mode and a seek (or velocity) mode, each mode employing a variety of compensation functions. A second embodiment includes a single comprehensive control system which functions during both tracking and seek operations.

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: A method for reducing noise during track seeking in a disc drive wherein transducers proximate the surfaces of discs of the drive are accelerated away from an initial track in a first sequence of successive time interval and subsequently decelerated toward a destination track in a second sequence of successive time intervals in proportion to the difference between the actual velocity of the transducers and a demand velocity for each of the intervals. The demand velocity in each time interval is the sum of the demand velocity for the previous interval and a velocity demand fraction of the difference between an adjusted profile velocity and the demand velocity for the previous time interval. The adjusted profile velocity is the difference between a stored profile velocity and an anticipator that is maintained at a selected value during acceleration of the transducers and decremented to zero during initial time intervals in which the transducers are decelerated.

Abstract: In a rotation synchronous control system comprising a host controller and a plurality of units connected to the host controller, each of the plurality of units having a rotation device, the system having a spindle sync function for the rotation devices to maintain a spindle sync between them, each of the units is provided with a spindle sync/reference signal source and a phase adjuster. The controller monitors the spindle sync between the units and issues a phase correction instruction to each of the units. Receiving the instruction, the phase adjuster in each unit adjusts the phase of the sync signal and uses the sync signal thus corrected to provide a spindle sync control.

Abstract: A method and A circuit for detecting an auto tracking find error in a VCR, wherein a phase control range for a capstan motor is widened as compared with the prior art so that, when a phase of the capstan motor is widely detuned, the following speed for stabilization of the phase of the capstan motor can be made fast. According to the invention, in an interval of -.pi.-.pi. of the phase of the capstan motor, first latch data is selected as a phase error signal for control of the phase of the capstan motor. In intervals of -2.pi.--.pi. and .pi.-2.pi. of the phase of the capstan motor, second latch data is multiplied by two and is then of the same polarity as that of the first latch data. The second latch data multiplied by two is added to the first latch data. In result, the added value is selected as the phase error signal. Also, a portion of the data above double the upper limit value is cut in the interval of -2.pi.--.pi.

Abstract: An apparatus for controlling the phase of a video signal has a track information detector for extracting track pair number data allotted to every N tracks from a reproduced signal when a rotary head is locked in phase with a reference signal, an FG generator, an FG counter for counting pulses of a capstan motor frequency signal, and a microcomputer for producing shift quantity data representing a shift quantity by which the rotary head is to be shifted to a target phase lock position, based on a value indicated by the track pair number data and a value indicated by the count from the FG counter, and controlling a capstan motor based on the shift quantity data, and output signals from a speed detector and a phase detector. The apparatus is capable of preventing an asynchronous condition from occurring upon switching between internal and external signals in an A/B editing process or the like.

Abstract: A time coding system of high resolution for a digital audio and video recording system is disclosed. Various methods of structuring: time code for recording are disclosed which enable time code reading at high tape transport speeds to facilitate automatic search/forward and reverse. A time and control code generator for video recording and replay use comprises a pulse generator generating a pulse having a television frame frequency repetition rate. A source of a time code signal is related to the television frame frequency, and comprises data bits representing hours minutes seconds and frames. A pulse position modulation means is coupled to the pulse and in response to the data its representing hours minutes seconds, modulates a trailing edge of the pulse to a first position responsive to the data bits having a logical 1 value and modulates the trailing edge to a second position responsive to the data bits having a logical 0 value.

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: A servo control system provides adaptive compensation for a variety of tracking and seek problems found in disk drive. The servo control system is ideally implemented in digital form for accuracy, speed and compactness. A first embodiment includes two modes, a tracking (or position) mode and a seek (or velocity) mode, each mode employing a variety of compensation functions. A second embodiment includes a single comprehensive control system which functions during both tracking and seek operations.

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: To edit reproduced audio and video signals for recording onto a recording medium, the start point of a first reproduced signal, reproduced from a first playback medium, is synchronized to a first reference time. The end point of the first reproduced signal and the start point of a second reproduced signal, reproduced from a second playback medium, are synchronized to a second reference time. The end point of the second reproduced signal is synchronized to a third reference time. The start and end points of a third reproduced signal, reproduced from a third playback medium, are respectively synchronized to the first and third reference times. The first and second reproduced signals are sequentially delivered to the recording medium as a function of the first, second and third reference times, and the third reproduced signal is delivered to the recording medium as a function of the first and third reference times.

Abstract: A method and apparatus are provided for servo demodulation in a direct access storage device. A readback signal is sensed from at least one disk surface and locations of positive and negative peaks in the sensed readback signal are detected for providing a detected peak signal. A square wave signal having a period variable with distance between detected locations of positive and negative peaks is generated using the detected peak signal and applied to a servo demodulator in the direct access storage device.

Abstract: In a tracking control circuit for a rotary head type magnetic recording/reproducing apparatus, the feed speed of the magnetic tape is controlled in response to an average value of plural tracking error information data detected from at least two or more locations on a recording track, whereby a tracking error can be corrected with high accuracy even when the plural tracking error information data are reproduced at unequal intervals.

Abstract: A multi-track servo recording head includes a multi-tip write core for simultaneously writing a plurality of tracking signals on magnetic storage media. The magnetic recording head may include an optical edge sensor and a magnetic edge sensor for sensing the position of the recording head relative to the edge of the storage media. Additionally, a read core is provided to detect the longitudinal position of the storage media relative to the recording head during media transport.

Abstract: Digital video tape recorder for recording and reproducing digital video and audio data in respective tracks in a predetermined format on a record medium. The predetermined format having respective video, audio and subcode areas with each area having a number of sync blocks comprised of a data area in which video, audio and system data, respectively, are recorded. These areas are preceded by a fixed area in which sync block identifying information is recorded. The data area of the subcode area is formed of data packs having a common pack structure and system data provides for automatic control during reproduction and for identifying the recorded digital video and audio data.

Abstract: A magnetic or optical disc device which can correctly follow the eccentricity of an eccentrically chucked disk and Which can immediately follow the eccentricity of the new disk face when there is a changeover of the disc being accessed operates with a disc having data tracks provided with uniformly spaced clock marks for providing a timing standard and includes a reproduction circuit for reproducing data from the disc, a clock sampling circuit for extracting a first clock signal output by the reproduciton circuit, an eccentricity magnitude memory section for storing a signal corresponding to the eccentricity of the data tracks with respect to the axis of rotation of the disc; a clock correction section.

Abstract: During a write revolution of a storage medium, a transition is written on the storage medium while servoing on another transition previously recorded on the storage medium. During that write revolution, a position error signal corresponding to the position error of the transducer relative to the previously recorded transition is determined. That position error signal is then stored, during the write revolution, to be used in computing a reference track value associated with the transition being written to correct for the position error. Additionally, a product servo-pattern is written, which includes an embodying of the position error therein.

Abstract: A cassette deck of a car stereo has at least one capstan and a motor for driving the capstan. An accessory switch is provided in a car provided with the car stereo. A accessory switch detector is provided for detecting closing of the accessory switch. A cassette detector is provided for detecting setting of a cassette to the cassette deck. In response to detection of closing of the accessory switch, and setting of the cassette, the motor is operated for rotating the capstan for a predetermined time.