摘要:
A track search apparatus is composed of an actuator such as voice coil motor for moving a light beam to traverse tracks, a position detector for detecting that the light beam has reached a predetermined position in front of a target track, a velocity detector for detecting the velocity of the light beam, and acceleration/deceleration controller such as microcomputer for applying, to the actuator, a driving signal according to the output from the velocity detector when a signal is generated from the position detector.
摘要:
The temperature around the tracking actuator is detected with a temperature sensor, and the characteristics of an equivalent digital filter are changed to match the characteristics of the tracking actuator at the detected temperature. When the temperature is low, a current is applied to the focus control coil to raise the temperature of the tracking actuator, thereby essentially matching the transfer functions of the tracking actuator and the equivalent filter.
摘要:
A tracking control target position adjusting track is provided on a recording carrier, where the track contains a preliminarily recorded first position-adjusting signal adjoining one side of track and a second position-adjusting signal adjoining the other side of track. While the reproduction position set on the target-position adjusting track, the tracking control apparatus adjusts the tracking-control target position based on reproduced first and second position-adjusting signals. As a result, the tracking control apparatus can precisely adjust the tracking control target position, thus providing quite satisfactory interchangeability with the corresponding apparatuses.
摘要:
A velocity detection method and an apparatus therefor, in which the relative velocity between a light beam and tracks is detected on the basis of a period for which the light beam crosses the tracks, and under the condition that the light beam has passed by a predetermined position on the way to the target track, the detected relative velocity is compared with a predetermined velocity value so that when the detected relative velocity is larger than the predetermined velocity value the detected relative velocity is invalidated on the assumption that erroneous detection is generated by noise.
摘要:
A system for recording or reproducing a signal by focusing and irradiating a light beam on a record carrier from a light source while controlling the light beam to always scan the track on the record carrier is disclosed. A track jump that may occur during recording or reproducing a signal on the record carrier is accurately detected. The reliability of the system is thus improved in such a way as to take appropriate action in case of a track jump.
摘要:
A recording and reproduction apparatus for recording signals on a recording medium or reproducing signals recorded on the recording medium, which is so arranged that, with acceleration detectors being provided for detecting accelerations of the apparatus by vibrations or impacts applied from outside, signals from the acceleration detectors are applied to control section for stabilization of the control system and also, for proper treatment upon application of excessively large external vibrations or impacts, with consequent improvements of reliability and stability of the apparatus.
摘要:
A focusing control apparatus is provided for controlling focusing of a light beam on a recording medium. The apparatus includes a control mechanism for maintaining the focusing state of the light beam on the recording medium by moving a focus mechanism based on a comparison between an output signal indicative of the focusing state and a target value. The apparatus further includes a target value setting circuit for setting the target value at a first level when the light beam is irradiated on the land track portions of the recording medium; and for setting the target value at a second level when the light beam is irradiated on the groove track portions.
摘要:
A data-track search apparatus is provided with: a tracking error detection unit for detecting a positioning error between a light beam on a record carrier and a track; a moving unit for moving the light beam on the record carrier in a direction traversing the tracks on the record carrier; a focusing control failure detection unit for detecting a focusing control failure, and a control unit for controlling the moving unit in response to an output signal from the tracking error detection unit during the search for a desired track. The control unit regulates the moving unit so as not to accelerate but to decelerate the moving unit in the event of a focusing control failure.
摘要:
A data recording/reproducing device has a pickup for recording/reproducing information on disk which has tracks formed on a recording area and a ROM area. A track access device for moving the pickup from a starting track at which the pickup is presently located to a target track includes a moving arrangement for moving the pickup in a direction crossing tracks, a tracking error signal generator for generating an analog signal representing the crossing of the tracks by the pickup, and position detector for detecting the position of the pickup in either one of the recording and ROM areas. Also, for processing the tracking error signal, an amplifier, an offset adder and hysteresis comparator are provided, each having differing operating parameters when the pickup is located in the recording area and then when it is located in the ROM area.
摘要:
In an apparatus in which information is reproduced by projecting/receiving an optical beam to/from a recording carrier having a large number of information tracks, tracking control is performed so as to maintain a reproducing position on an information track by supplying a track deviation signal to an actuator. If this track deviation signal becomes asymmetric by an inclination, etc. of the recording carrier so that a shock is applied to the apparatus, jumping out of a track occurs, resulting in slip-off of the optical beam from the reproducing position. This slip-off can be prevented by detecting a position of a movable support member carrying a focusing lens for projecting and receiving the optical beam and feeding back the position signal to the tracking control system, or by extracting a low-frequency component of an output signal of a control circuit and feeding back the extracted signal to the tracking control system.