Pioneer Electronic Corporation

Hiroyuki Hirano

Ryuichi Naito

Fumihiko Yokogawa

Shinichi Naohara

Katsumi Ishii

Kanya Matsumoto

Hiroshi Yokota

Yoshifumi Tsukada

Keiichi Matsumoto

Toshiyuki Kimura

Akira Haeno

Susumu Niinuma

Takashi Sato

Yoshihiko Watanabe

Minoru Yoshioka

Ryozi Higashi

Youichi Ogawa

Yoshiro Nishi

Akira Motoyama

Keiji Kinpara

Yoshiro Aoyagi

Yoshio Aoyagi

Sumio Hosaka

Toshihiko Kurihara

Taichi Akiba

Kyota Funamoto

Saburo Takaoka

Yoshiki Furuta

Yositsugu Araki

Atsushi Kimura

Yoshifumi Tsukuda

Hiroshi Horii

A disc player has a first array of pickup devices arranged in a line for reading information from a disc and a second array of pickup devices arranged in a parallel line. The pickup devices are each independently movable along their respective lines with the devices of the first line offset from the devices of the second line so as to form a zigzag pattern.

Disc player with objective lens arranged in a zigzag pattern

A recording medium playing apparatus allows an arbitrary and easy selection and reproduction of each information piece of a recording medium carrying a plurality of information pieces which variously represent a scene on the same time axis position during reproduction of information. In the recording medium playing apparatus for playing a recording medium on which same-time information groups each formed by a plurality of information pieces of the same time position are recorded, reproducing means for reproducing information of the recording medium reproduces information of the recording medium by arbitrarily selecting each information piece of the recording medium based on a command for reproducing each same-time information group.

Recording medium playing apparatus for reproducing same time information

A disc player includes: a plurality of pickup devices for reading information from a disc and a plurality of guide devices arranged radiately from a center of the disc, each for radially transferring one of the pickup devices. The guide devices are arranged so that each alternate pickup device is raised or lowered toward the inner circumferential portion of the disc.

Disc player with alternating ascending/descending guide devices

A disc player includes at least one pickup device, which includes a pair of objective lenses for reading information from a disc. The pair of objective lenses are independently movable in the radial direction of the disc by a magnetic field generated by a common magnet.

Disc player with parallel objective lenses

A disc player includes: a plurality of pickup devices for reading information from a disc; and a plurality of guide devices having a longitudinal axis for transferring the pickup device, the longitudinal axis being directed in a direction rotated by a predetermined angle with respect to a radial direction of the disc.

Disc player

A PLL circuit, to which an input signal is inputted, is provided with: a voltage controlled oscillator for outputting an output signal; a control voltage generation circuit for generating a control voltage to lock phases of the input and output signals by a loop, and outputting the generated control voltage to a control input terminal of the voltage controlled oscillator; and a central frequency setting circuit for setting a central frequency, to which a frequency of the output signal is to be pulled-in, to the control voltage generation circuit. A pulling-in circuit for the PLL circuit is provided with: a sweep range setting circuit for setting a sweep range, where the frequency of the output signal is to be pulled-in to the set central frequency, on the basis of the set central frequency; a lock detector for detecting whether or not a pulling-in operation is completed in the PLL circuit, and outputting a lock signal when the pulling-in operation is detected to be completed; and a sweep range control circuit for controlling the control signal generation circuit to generate the control signal to repeatedly sweep the frequency of the output signal through the set sweep range during the pulling-in operation until the lock signal is supplied thereto.

Pulling-in circuit for PLL circuit, pulling-in method for PLL circuit,

A record medium of disc type is recorded by a constant linear velocity. The record medium is reproduced by a reproducing apparatus, which reads the information from the rotated record medium into a buffer memory by a transmission rate corresponding to the number of rotation of the record medium and outputs the read information from the buffer memory to an external apparatus by a predetermined output rate. The method of reproducing the record medium by the reproducing apparatus is provided with the steps of: setting radial ranges of a plurality of virtual zones on the record medium, each of which is in a ring shape, and the number of rotation for each of the virtual zones, on the basis of upper and lower limit values of the transmission rate, which are predetermined to be higher than the predetermined output rate, a radius of the most inner circumference of an area where the information is recorded on the record medium, and a memory capacity of the buffer memory; rotating the record medium by a constant angular velocity in each of the set virtual zones by the set number of rotation; and reading the information from the rotated record medium by the transmission rate corresponding to the set number of rotation in each of the set virtual zones.

Method and apparatus for reproducing information recorded on CLV disc

A recording-reproducing clock generator circuit generates a reproduced clock having a predetermined frequency from a read out signal including such pulses that the interval between two successive pulses thereof at a predetermined length is to be used as a synchronizing signal region. The circuit generates a reference clock of a predetermined frequency, generates a first sync signal detection signal when the distance between two successive pulses in the input signal measured by means of the clock pulses is equal to a predetermined reference value, separates a clock edge pulse from the input signal by using the first sync signal detection signal, and generates the reproduced clock having the predetermined frequency and synchronized with the separated clock edge pulse.

Clock generator circuit and a synchronizing signal detection method in a

A circuit for computing a tracking error signal digitally. Under control of appropriate timing, input RF signals are latched in successive latches, and outputs of the latches are compared. The latch (9) whose output is D/A converted as a tracking error signal is controlled by suitable logic (25) to latch an output of a preceding latch (8), that output being used to provide input to the logic (25) through a threshold circuitry which includes adders (21,22) and comparators (14,15). The circuit takes advantage of servo patterns on surfaces of disks, particularly optical disks, to provide track count and on-track status. The digital approach removes the necessity for using capacitors or other types of sample-and-hold circuitry, and for controlling offset values.

Circuit for digitally generating a tracking error signal to avoid offset

An optical disk data recording and reproducing apparatus includes variable delay circuits in the recording and reproducing sections of the apparatus. The delay of the reproducing section delay circuit is adjusted when the error ratio determined for a reproduced data signal corresponding to a recorded data signal is greater than a predetermined value. When the error ratio is less than the predetermined value after adjustment of the delay circuit, the delay of the delay circuit in the recording section is adjusted to match the adjusted delay of the reproducing section delay circuit and the delay of the latter circuit is retured to its original value.

Method and apparatus for data recording and reproducing with error

A disc player comprising a signal pickup unit to read information from a disc on which program information including address information is recorded, the signal pickup unit being movable with respect to the disc, pickup drive means to drive the pickup unit for movement with respect to the disc, and a control circuit including an address memory for storing the newest one of the addresses read from the disc, a counter operative to count addresses at predetermined time intervals for producing a signal representative of an expected address indicative of the position to which the pickup unit is expected to move in the next, the expected address being updated at predetermined time intervals, a detector circuit to produce a signal each time a discrepancy is found to exist between the newest address and the expected address. In response to the signal from the detector circuit, the pickup drive means is actuated to drive the pickup unit for movement to the position dictated by the newest address or the expected address.

Automatic loading disc player

A servo circuit for use in an optical disk player or the like, which can track a disk having a large eccentrically without abnormal sampling of the RF signal produced as a result of scanning the disk. The servo circuit according to this invention comprises a first comparator for comparing RF signals from a pair wobbled pits on a optical disk and generating a difference signal indicating the level difference between the AF signals; a holding means for holding the difference signal for a predetermined period; a reference level producing circuit for setting reference levels having a predetermined width with the level of a previously sampled difference signal of the holding means as a center; a second comparator for comparing the level of a presently sampled difference signal of the first comparator with the reference level and outputting a first signal indicative of the comparative result; and a selector for selecting and outputting, as a tracking error signal, either the presently sampled difference signal and a second signal having a level within the predetermined width of the reference level in accordance with the comparative result. The presently sampled difference signal is selected when the level of the presently sampled difference signal is within the reference level and the second signal is related when the presently sampled difference signal is out of the reference level.

Servo circuit for generating a tracking error signal for optical disk

In a programmed reproduction system provided for a still picture recording/reproduction device in accordance with the present invention, a plurality of groups of data are recorded on a recording disk by a disk recording/reproduction means; a program indicating the sequence of reproduction of the plurality of groups of data is recorded in a prescribed recording position on the recording disk by the disk recording/reproduction means; the program recorded in the prescribed recording position is read by the disk recording/reproduction means in response to a command; and still pictures are reproduced from the plurality of groups of data in the sequence of reproduction indicated by the read program. For that reason, a manual operation for inputting the program does not need to be performed after the program is recorded on the disk. The operating property of the still picture recording/reproduction device is thus improved.

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Tokorozawa, Japan

Hiroyuki Hirano