Pioneer Electronic Corporation

Ryuichi Naito

Hiroyuki Hirano

Shinichi Naohara

Katsumi Ishii

Kanya Matsumoto

Hiroshi Yokota

Yoshifumi Tsukada

Fumihiko Yokogawa

Ikuya Kikuchi

Saburo Takaoka

Minoru Kosaka

Katsumi Kawamura

Tsuneo Ishii

Yoshihiro Utsumi

Youichi Ogawa

Tadahiro Yamaguchi

Keiji Kinpara

Megumi Tanaka

Yoshifumi Tsukuda

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 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

An optical disc recording apparatus for dividing an information record surface of an optical disc into a plurality of record zones and recording information at a data rate which differs for every record zone, is provided with: a drive device for rotationally driving the optical disc by a constant angular velocity; a frequency conversion device for converting a clock frequency of input clock data corresponding to record data inputted from the external which is to be recorded on the optical disc, to record clock data corresponding to the record zone to be recorded, and outputting the record clock data; a memory device for storing the record data by a timing corresponding to the input clock data, and outputting the record data on the basis of the record clock data; and a record device for recording the record data outputted from the memory device, to the optical disc.

Optical disc with data recorded at different rates on different zones

An opto-magnetic disk unit is constructed so that predetermined areas existing in the front of the unit recording areas can be detected. In addition, at least one of first and second saturation magnetizations are recorded on each of the detected predetermined areas. At the time of reproduction, signal processing on the output of the pickup is performed after a part of the output of the pickup corresponding to the one section of the predetermined area is clamped to a predetermined level. Also at the time of reproduction, gain controlling of a circuit for signal processing the output of the pickup may be performed based on the level difference between the signal read from a first saturation magnetization section and the signal read from a second saturation magnetization section. An opto-magnetic disk is also provided having recording areas including at least one of first and second magnetization saturation levels arranged in the front of the unit recording areas.

Opto-magnetic disk unit with improved dynamic range characteristics and

An autochanger of writable discs automatically transfers a write-once optical disc between a disc accommodation unit and a recording/reading device where data are recorded into the optical disc and read from that. In order to shorten a disc loading time, address information of sectors in which the latest defect management information is stored is written into an erasable non-volatile memory IC and renewed when a new defect sector is found in the optical disc.

Autochanger of writable discs

An autochanger of writable discs automatically transfers a write-once optical disc between a disc accommodation unit and a recording/reading device where data is recorded into and read from the optical disc. In order to shorten a disc loading time, the latest defect management information is stored in a floppy disc and renewed when a new defective sector is found in the optical disc.

Autochanger of writable discs including a non-volatile memory for

In a finally recorded sector detecting system suitable for a write-once type optical disc device, an error correction code or error detection code provided for each index sector is utilized to detect a state of errors occurring in reproduced index signals, and a finally recorded index sector is determined from the state of errors thus detected.

Method and apparatus for detecting finally recorded sector

A clock of a predetermined frequency is generated on a basis of clock information contained in a read signal. Sample values obtained by sampling the read signal in response to the clock are sequentially converted into digital data, and the thus obtained digital data are held in a first data holding means and then second data holding means in response to the clock for a time corresponding to the clock. The digital data and the output data from the second data holding means are added, and the addition output bits are multiplied by a predetermined constant by inserting a selected number of zero bits as upper significant bits, and shifting the addition output bits by the selected number of zero bits. Data corresponding to the difference between the multiplied output and the output of the first data holding means is obtained, and the thus obtained difference output is demodulated in response to the clock.

Recorded data demodulation circuit

A read-out information signal processing circuit having a switching device for relaying the read-out information signal read-out from a recording medium in an optical recording and reproducing system. The read-out information signal relayed by the switching device is supplied to an A/D converting circuit through DC interrupt means. The switching device is turned off during the recording period. Thus, the variations of DC level supplied to the A/D converting circuit at the transient time from a recording mode to a reproducing mode can be prevented and the dynamic range of A/D converting circuit can be effectively used.

Read-out information signal processing circuit in an optical recording

A photoelectric converting circuit including a light-receiving element which produces a current signal corresponding to the amount of light incident upon it and a current-to-voltage converting circuit which converts the current signal to a voltage signal. The circuit is characterized in that the current signal is supplied to the current-to-voltage converting circuit through an active circuit which exhibits a low input impedance. In preferred embodiments, the active circuit is a common-base transistor circuit in which an emitter current is supplied to the light-receiving element and a collector voltage is outputted as an output signal.

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Tokorozawa, Japan

Ryuichi Naito