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公开(公告)号：US5101391A
公开(公告)日：1992-03-31
申请号：US414510
申请日：1989-09-29
CPC分类号： G11B7/0941
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.
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公开(公告)号：US5105402A
公开(公告)日：1992-04-14
申请号：US408242
申请日：1989-09-18
CPC分类号： G11B19/02 , G11B21/083
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.
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公开(公告)号：US5084849A
公开(公告)日：1992-01-28
申请号：US433685
申请日：1989-11-08
CPC分类号： G11B7/0941
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.
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公开(公告)号：US5245599A
公开(公告)日：1993-09-14
申请号：US416790
申请日：1989-10-05
IPC分类号： G11B7/09
CPC分类号： G11B7/00375 , G11B7/08523 , G11B7/0941 , G11B7/0946 , G11B7/0948
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.
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5.发明授权Servo system responsive to noise and having variable characteristic filter means 失效响应噪声和具有可变特性滤波器的伺服系统
公开(公告)号：US5065386A
公开(公告)日：1991-11-12
申请号：US452703
申请日：1989-12-14
CPC分类号： G11B20/10009 , G11B20/10527 , G11B20/18
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.
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公开(公告)号：US5050149A
公开(公告)日：1991-09-17
申请号：US378937
申请日：1989-07-12
CPC分类号： G11B7/0941
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.
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公开(公告)号：US5150344A
公开(公告)日：1992-09-22
申请号：US483705
申请日：1990-02-23
CPC分类号： G11B7/0946
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.
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公开(公告)号：US5187696A
公开(公告)日：1993-02-16
申请号：US398875
申请日：1989-08-28
申请人： Hidehiro Ishii , Hiroshi Takeya , Chiharu Miura , Tatsuya Fukuda
发明人： Hidehiro Ishii , Hiroshi Takeya , Chiharu Miura , Tatsuya Fukuda
CPC分类号： G11B7/0941 , G11B19/06 , G11B19/20 , G11B19/22
摘要： 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.
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公开(公告)号：US4885644A
公开(公告)日：1989-12-05
申请号：US288190
申请日：1988-12-22
申请人： Hidehiro Ishii , Junichi Yoshio , Osamu Watanabe , Takeshi Izumo , Noriyoshi Takeya , Kazuhiko Katakami , Masayori Shinohara , Masao Yoshida
发明人： Hidehiro Ishii , Junichi Yoshio , Osamu Watanabe , Takeshi Izumo , Noriyoshi Takeya , Kazuhiko Katakami , Masayori Shinohara , Masao Yoshida
CPC分类号： H04N9/802 , G11B19/12 , G11B19/28 , G11B20/00 , G11B27/002 , G11B27/105 , G11B27/28 , G11B2220/2545
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.
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公开(公告)号：US4872068A
公开(公告)日：1989-10-03
申请号：US149763
申请日：1988-01-27
申请人： Hidehiro Ishii , Junichi Yoshio , Osamu Watanabe , Takeshi Izumo , Noriyoshi Takeya , Kazuhiko Katakami , Masayori Shinohara , Masao Yoshida
发明人： Hidehiro Ishii , Junichi Yoshio , Osamu Watanabe , Takeshi Izumo , Noriyoshi Takeya , Kazuhiko Katakami , Masayori Shinohara , Masao Yoshida
CPC分类号： H04N9/802 , G11B19/12 , G11B19/28 , G11B20/00 , G11B27/002 , G11B27/105 , G11B27/28 , G11B2220/2545
摘要： 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.
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