Abstract: 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.

Abstract: A method for setting the loop gain in a focusing servo loop of a disc player. The loop is opened and the objective lens is moved repeatedly up and down about the focusing point while the disc is slowly rotated, thereby generating an S-shaped focusing error curve. The S-shaped error curve is sampled and a loop gain is determined based on the sampled values. If an eject instruction occurs during the loop gain setting process, a braking pulse is applied to a spindle motor for stopping the disc rotation.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: In a disk player, a tilt detection signal is generated corresponding to a tilt of a recording surface of a disk relative to a reference plane depending on a position of a pickup or a pickup radial position is generated. A reproduced video signal is passed through a noise reduction circuit having a transfer function which is changed in accordance with the tilt detection signal or the radial position signal so as to reduce a noise component. Accordingly, the influence of cross-talk on a picture caused by the tilt of the disk can be electrically reduced, and a complicated mechanism becomes unnecessary, so that it is possible to simplify the structure of the player. Moreover, it is not necessary to select a pickup in which the quantity of cross-talk is small against a tilt of a disk, so that it is possible to make the production cost low.

Abstract: 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.

Abstract: An apparatus and a method of stopping a spindle motor for rotating a composite disk in a disk player. The composite disk contains a first area having information recorded thereon at a first rotational frequency, and a second area having information recorded thereon at a second rotational frequency which is greater than the first rotational frequency. The spindle motor is stopped when a stop or eject command is instructed during or after information is read from the second area of the composite disk by moving a pickup for reproducing information recorded on the disk to the first area and supplying a counter torque brake signal to the spindle motor, thereby slowing the rotational frequency of the disk to a rotational frequency in which information can be read from the first area. A further counter torque brake signal is supplied to the spindle motor for a predetermined amount of time after the moved pickup begins to read information recorded on the first area to thereby stop the rotation of the composite disk.

Abstract: 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.

Abstract: 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.

Abstract: A method and device for playing a composite disk containing separate audio-only and video-plus-audio portions in which the time until the commencement of the playing of the video-plus-audio portion is reduced. When playing of only the video-plus-audio portion is designated, a data detection point of the pickup is immediately moved toward the lead-in area of that portion, whereupon reproduction is started immediately. In another embodiment, index data is directly read from the lead-in area of the video-plus-audio portion without reading similar data for the audio-only portion. When the playing of the video-plus-audio portion is completed, the pickup is stopped at a rest position corresponding to the lead-in area of the second region.

Abstract: A method and apparatus for playback of a data recording disc which contains a CD area in which a signal such as an audio signal is recorded in digital form and a video area in which a FM-modulated video signal is recorded with a digital audio signal superimposed thereon. The position of a data detection point of a pickup is monitored, and the equalization and amplifier gain of components of a digital demodulation system are automatically changed in accordance with playback being executed of the CD area or the video area, so that a single demodulation system is used for both digital signals from the CD area and digital signals from the video area. In addition, the frequency characteristics of components in servo systems which control the spindle motor, pickup carriage, etc. of the apparatus are automatically changed over for CD area and video area playback respectively, to provide stable servo control in spite of the high speed of rotation during video data playback.

Abstract: A clock signal generating circuit for a data reproducing device, such as a device in which an audio signal is digitized and recorded in multiplex form together with other signals such as video signals, on a magnetic recording medium, wherein the stability of the frequency of the clock signal is maintained even in the presence of drop-out of the audio, video or other signals. The clock signal generating circuit includes a voltage-controlled oscillator receiving as a frequency-control input signal the output of a phase comparator comparing the output of the voltage-controlled oscillator with a pulse train signal extracted from the RF signal read from the recording medium. The voltage-controlled oscillator receives a second control signal which causes it to maintain its present frequency. The second control signal is produced by ORing drop-out signals generated when FM signals obtained by subjecting the video and audio signals to frequency modulation are no longer present in the RF signal.