摘要:
In the tracking servo system according to the present invention, the noise removal means for removing a high-frequency noise component contained in the tracking error signal is in an operative state in normal playing operation, while the noise removal means is made to be in an inoperative state at least in an opened state of the servo loop.
摘要:
A method of setting the loop gain of a tracking servo loop of a disc player. The optimum loop gain is set for each playing of a disc without being influenced by disc eccentricity. The servo loop is opened, the disc is driven at a revolving speed which is lower than that of normal playback at the current position of the information reading spot, and a tracking error signal is obtained. The loop gain is set on the basis of a plurality of the sample values.
摘要:
A disc player operates in a manual search mode in which play and jump operations are alternately repeated, in response to a manual search command, while maintaining the reproducing level at a level lower than the level at the initiation of the manual search command as long as no change command appears.When the change command appears the reproducing level is shifted to a level which is designated by an operator so as to adjust the reproduced sound level to a level sufficient to listen to the reproduced sound for music selection.
摘要:
A loop gain setting method automatically sets the loop gain of a focus servo loop and a tracking servo loop of a disc player for playing a disc. Firstly the loop gains of the focus servo loop and the tracking servo loop are set, and subsequently the appropriateness of the set values of loop gains is judged by comparing the set values of the loop gains with each other. According to another aspect of the present invention the loop gains of the focus servo loop and the tracking servo loop are set, and subsequently the appropriateness of the set values of loop gains is judged by comparing at least one of the set values of the loop gains with a sensed value of the amplitude of the envelope of an RF signal read-out from the disc.
摘要:
A disc playing apparatus having a tracking servo loop and a focus servo loop is configured such that a transfer function of at least one of the servo loops is adjustable. Disc defect detection signals are generated in response to a change in a low frequency component and a high frequency component of a read signal output from the pickup, and the transfer function of at least one of the tracking servo loop and the focus servo loop is adjusted in response to the disc defect detection signals. According to another feature of the invention, the transfer function of at least one of the tracking servo loop and the focus servo loop is gradually changed each time an erroneous jumping movement of the information reading light spot is detected by information contained in the read signal output by the pickup.
摘要:
A servo system for a disc player having a pickup for reading information recorded on an information recording disc, includes an A/D converter for converting an error signal produced on the basis of signals output from the pickup into a digital signal, and performs driving and control of the pick up according to the signal level of the error signal having been processed digitally. The servo system further comprises a filter circuit permitting low frequency components of the error signal to pass therethrough and supplying the low frequency components to the A/D converter, detection circuit detecting noise components having levels higher than a predetermined level, contained in the error signal, and a circuit generating a control signal for a predetermined period after an instant of detection of the noise components by the detection circuit. The filter circuit has a first transmission characteristic with a cut-off frequency below one half of a sampling frequency of the A/D converter when the control signal is absent, and a second transmission characteristic with another cut-off frequency lower than the cut-off frequency when the control signal is present.
摘要:
A disc player having digital processing of error signals in a servo system utilizes an A/D converter. The relatively small closed loop error signals are amplified by a predetermined amount above that for the open loop error signals prior to conversion in the A/D converter, and the converter output representing the digitized small error signals are amplified by a predetermined amount below that for the digitized open loop error signals. While the overall gain in the servo system is substantially the same for the closed loop and open loop error signals, the small closed loop error signals are greatly expanded in range at the converter input to permit the same A/D converter to faithfully convert both the open loop and the closed loop error signals.
摘要:
A servo apparatus for an optical disk player which coarsely adjusts the loop gain in advance in an open state of a servo loop, and then closes the servo loop to finely adjust the loop gain. This ensures accurate and sure gain control even if there are differences between reflection factors of the recording surfaces of disks being played or is a stain or the like on an objective lens of the player.
摘要:
A magazine-housed disk reproducing apparatus is disclosed which enables the user to easily determine the contents of the various disks contained in the magazine. The names of tunes and the like provided on the various available disks are stored in a memory. An identifying device detects which magazines containing which disks have been loaded. A display device is activated to indicate to the user the desired content information.
摘要:
An apparatus for playing a composite disk containing separate audio-only and video-plus-audio portions, as well as an ordinary compact disk. It is first detected whether the disk being played is a compact disk or a composite disk, and if the disk is a composite disk, whether the portion presently being played is a region containing only audio data or a region containing a frequency modulated video signal recorded in multiplex form with a digital signal. A reference signal for driving a spindle servo circuit is produced as a fixed frequency signal when the disk is a composite disk or the region of a composite disk being played contains only audio data, and as a variable frequency signal of frequency determined in accordance with the frame sync signal contained in the reproduced signal when a region of a composite disk containing a multiplex-type signal is being reproduced.