摘要:
A digital servo controller generates a control signal from an analog observation signal using an output equation, state equation or a transfer function, and performs high precision servo-control with an inexpensive configuration. In a digital servo which executes an output equation ydnullknullnullCnullxnullknullnullDnulludnullknull and state equation xnullknull1nullnullAnullxnullknullnullBnulludnullknull. The digital servo comprises a digital processor which outputs the second term Dnulludnullknull of the output equation by an analog circuit, and outputs the first term Cnullxnullknull earlier for Ts/2. The digital servo also comprises a digital processor which executes the direct term of the output equation at period Ts/N (N is a 2 or higher natural number), which is 1/N of the basic operation period Ts, and updates the first term with the same delay time as the average delay time Ts/(2N) of the direct term. Also the digital servo comprises a digital processor which outputs the term null0 of the transfer function by the analog circuit, and outputs the other terms earlier for Ts/2. Also the digital servo comprises a digital processor which executes the term null0 of the transfer function at period Ts/N which is 1/N of the basic operation period Ts, and updates the other terms with the same delay time as the average delay time Ts/(2N) of the direct term.
摘要:
A DPD tracking error generating section generates a DPD tracking error signal from a plurality of sense signals supplied from an optical sensor. A PP tracking error generating section generates a PP tracking error signal from a plurality of sense signals supplied from the optical sensor. The amplitude of each of the DPD tracking error signal and PP tracking error signal is adjusted suitably under the control of a CPU. The suitably adjusted signals are added by an adder, thereby generating a tracking error signal.
摘要:
An optical disk device that performs a stable seek operation even in the movement from a recorded surface to an unrecorded surface. The optical disk device has gain corrector 30. The gain corrector comprises memory section 22 for storing a gain control value of the AS control system before a rough seek, movement determining section 23 for determining if the rough seek has made a movement from a recorded surface to an unrecorded surface, and computing and setting section 24 for correcting a gain control value of the tracking control system. When it is determined that the rough seek is performed from a recorded surface to an unrecorded surface, the gain corrector corrects the gain control value of the tracking control system according to the rate of change in the gains of the AS control system before and after the rough seek. This correction can prevent saturation of gains of the tracking control system and thus provide a stable rough seek.
摘要:
An optical pickup device including a lead frame and a board attached to the lead frame is provided. The lead frame includes optical components, such as a laser diode and an optical element, which are disposed within a lead frame. A photo diode is mounted on the board to receive a beam transmitted through the optical element. The board is adjusted with respect to the lead frame using the beam before attached to the lead frame. An upper opening and a lower opening are formed on an upper side and a lower side of the lead frame, respectively. An optical element installation space formed within the lead frame and defined by an upper side walls and an optical element support. A hole is formed in a central portion of the optical element support and communicates with the optical element installation space and a photo diode installation space which is defined by the optical element support and a lower side wall of lead frame. The laser diode emitting the beam is mounted on a laser diode support which is formed adjacent to the optical element support in the optical element installation space. The optical element mounted on the optical element support is disposed within the optical element installation space to direct the laser beam emitted from the laser diode toward an optical medium through upper opening and to transmit the laser beam to the photo diode of the board.
摘要:
An optical disk apparatus includes an optical detector which has light receiving areas divided nearly concentrically with an optical beam and outputs a signal corresponding to the amount of the reflected light from an optical disk. A surface vicinity detecting section adds up signals from all the light-receiving areas of the optical detector and outputs a detection signal. The detection signal continuously varies so as to have one maximum level while a beam spot of the optical beam moves from the surface of the information medium to the information plane. An information plane detecting section judges that the focus or the beam spot of the optical beam comes closer to the information plane of the optical disk by detecting the gradient of the detection signal. An approach of a condensing lens and the optical disk is judged based on the judgment results, and thus a collision of the condensing lens and the optical disk can be prevented.
摘要:
A record carrier is described that has a servo track (4) indicating an information track (9) intended for recording information blocks. The servo track (4) has a periodic variation of a physical parameter at a predetermined frequency and modulated parts for encoding position information at regular intervals. The modulated parts start with a bit sync element and are of a data type having a data bit element or of a word sync type having a word sync element. The bit sync element, word sync element and the data bit element being modulated according to a same predetermined type of modulation of the periodic variation. The distances between all elements constituting the modulated parts are unique. Further a device for reading and/or writing the record carrier is described.
摘要:
The present invention aims to obtain a position control device which, even if the range within which a mechanical part can be pulled in for position control is narrow, enables quickly stabilizing the pull-in operation. It provides a position control apparatus which includes position error signal detection means (15a, 15c) for detecting a position error signal of the mechanical part and position control means (21a, 21b, 21c) for controlling the position of the mechanical part by supplying to it the position error signal from the position error signal detection means (15a, 15c), whereby the apparatus has provided therein phase compensation means (18) comprising a digital filter; the position error signal is supplied to the phase compensation means (18) to perform phase compensation thereon and the phase-compensated position error signal is supplied to the position control means (21a, 21b, 21c); and, when starting a closed-loop control, filter variables that were used at a time preceding by an amount of time equal to or greater than that corresponding to the amount of one sampling time of the digital filter (18) have been reset.
摘要:
A recording and/or reproducing apparatus for recording and/or reproducing data on or from an optical disc, in which the tracking error signal format for a recordable optical disc differs from that for a replay-only optical disc. The recording and/or reproducing apparatus includes a read-out processing unit for reading out data from the optical disc, a write processing unit for writing data on the optical disc and a system controller for managing control to verify the recordable optical disc having data recorded by the write processing unit by a reproducing system conforming to the standard for the replay-only optical disc. The recordable optical disc is verified by the reproducing system for the replay-only optical disc.
摘要:
A method of controlling an optical drive to perform a braking process in a layer jump process. The optical drive has a vertically movable pickup head, a preamplifier, a controller, and a low pass filter. The controller receives a focus error signal produced by the preamplifier to produce a focus control signal, and sends the focus control signal to the low pass filter to produce a layer distance balancing signal, so that the pickup head is controlled by the layer distance balancing signal to perform the layer jump process. The method of the present invention comprises the steps of: performing the braking process in accordance with a braking signal and the layer distance balancing signal when the focus error signal reaches a braking start point; and performing a closed-loop focusing control process when the focus error signal reaches a closed-loop focusing control point.
摘要:
An optical system of an optical recording apparatus forms a main spot and sub-spots preceding and succeeding the main spot on a signal recording medium. The optical system is set such that the sub-spot is shifted from the main spot in the direction orthogonal to a signal track by a distance expressed by an expression (2knull1) P/4 (knullnatural number), in which P denotes a distance between adjacent signal tracks on the signal recording medium. Thus, the sub-spot succeeding the main spot can be used to effectively read the state of a signal recorded on the signal recording medium by the main spot.