| 摘要 |
A tracking control arrangement for use in an optical disc player comprises a photodetecting assembly including a plurality of photodetecting elements each provided for receiving a light beam caused to impinge on an optical disc to read an information signal recorded in a record track thereon and reflected thereat and for producing an output in response to the received light beam, an operational circuit operative to generate from the outputs of the photodetecting elements a reproduced information signal and a resultant signal varying in phase relative to the reproduced information signal in response to the direction of deviation of a beam spot formed on the optical disc by the light beam from the center of the record track and varying in amplitude in response to the amount of the deviation, an error signal generating circuit operative to generate a tracking error signal in the form of voltage held by voltage holding means on the basis of both the reproduced information signal and the resultant signal obtained from the operational circuit and provided with discharging means for making the voltage holding means discharge to cause the tracking error signal to be zero or close to zero while the light beam is projected onto a non-reflecting portion of the optical disc, and a driving circuit for driving in response to the tracking error signal an optical device emitting the light beam to control the position of the beam spot on the optical disc so that the beam spot is correctly located on the record track. |
