Patent EP0249462A1 successfully refreshed from Google Patents.
EP0249462A1
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EP
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Recording disk reproducing apparatus
Assignee: Pioneer Corp
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Filing: 1987-06-10
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Granted: —
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Expires: 2007-06-10
Abstract
Abstract A recording disk reproducing apparatus employing simplified digital servo control for lower-cost, more stable operational control of the apparatus. At least one of the focusing servo loop, (10,27) a tracking servo loop (11,28), a single servo loop, (12,30) and a time base servo loop (19,17) employs digital conversion of an analog error signal for processing in a microprocessor (14). The analog-to-digital conversion circuitry (13) has an input-output characteristic which varies in accordance with error signal level, enabling a reduction in the number of bits of A/D output necessary, and reducing cost.
Inventors
- 👤 Satoshi C/O Pioneer Electronic Corporation Kusano
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 14:51
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0941; G11B19/00; G11B19/20; G11B19/28; G11B20/00; G11B20/22; G11B20/225; G11B7/002; G11B7/0037; G11B7/0908; H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/93; H04N5/95; H04N5/953
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
214 words
Recording disk reproducing apparatus comprising: a pickup (1) for directing an optical beam onto a recording surface of a disk (7) containing recorded information, and for detecting information recorded on the disk by detecting light reflected from the recording surface; focusing servo means (10,27) for controlling the position of a focus of the optical beam so as to form an information detecting light spot from the pickup on the recording surface of the disk; tracking servo means (11,28) for controlling the relative position of the information detecting light spot in the radial direction of the disk: spindle servo means (12,30) for controlling motion of the information detecting light spot relative to the disk; characterised by; analog-to-digital coversion means (13) provided in at least one of the focusing servo means, tracking servo means, and spindle servo means, for analog-to-digital converting an error signal, an output of the analog-to-digital conversion means being subjected to operational processing for generating a driving signal for driving an actuator, the analog-to-digital conversion means having an input-output characteristic which varies according to the level of the error signal such that a change in the output relative to a change in the error signal is reduced when the level of the error signal is equal to or greater than a predetermined value.
Claim 2
Dependent Claim
214 words
Recording disk reproducing apparatus comprising: a pickup (1) for directing an optical beam onto a recording surface of a disk (7) containing recorded information, and for detecting information recorded on the disk by detecting light reflected from the recording surface; focusing servo means (10,27) for controlling the position of a focus of the optical beam so as to form an information detecting light spot from the pickup on the recording surface of the disk; tracking servo means (11,28) for controlling the relative position of the information detecting light spot in the radial direction of the disk: spindle servo means (12,30) for controlling motion of the information detecting light spot relative to the disk; characterised by; analog-to-digital coversion means (13) provided in at least one of the focusing servo means, tracking servo means, and spindle servo means, for analog-to-digital converting an error signal, an output of the analog-to-digital conversion means being subjected to operational processing for generating a driving signal for driving an actuator, the analog-to-digital conversion means having an input-output characteristic which varies according to the level of the error signal such that a change in the output relative to a change in the error signal is reduced when the level of the error signal is equal to or greater than a predetermined value.
Claim 3
Dependent Claim
106 words
Apparatus as claimed in claim 1, wherein the analog-to-digital conversion means (13) comprises: a plurality of serially-connected resistors (R₁ - R N+1 ) having different resistance values; a plurality of comparators (CP₁ - CP N ) each having their positive input terminals connected to a voltage division point between different pairs of the resistors, the error signal being provided at a negative input terminal of each of the comparators; and a matrix circuit (35) having its inputs connected to respective outputs of th comparators, wherein the matrix circuit generates digital data of a predetermined number of bits corresponding to an instantaneous level of said error signal.
Claim 4
Dependent Claim
41 words
Apparatus as claimed in claim 1 or claim 2, wherein the input-output characteristic of the analog-to-digital coversion means has a first gradient within a range defined by first and second input voltage values, and a second gradient outside of the range.
Claim 5
Dependent Claim
33 words
Apparatus as claimed in any of claims 1 to 3, wherein at least two of the focusing servo means, the tracking servo means, and the spindle servo means include the analog-to-digital conversion means.
Claim 6
Dependent Claim
70 words
Apparatus as claimed in any of claims 1 to 3, wherein each of the focus servo means, the tracking servo means, and the spindle servo means includes the analog-to-digital conversion means, the recording disk reproducing apparatus further comprising microprocessor means (14) for receiving outputs of the focus servo means, tracking servo means, and spindle servo means for providing digital servo control for reproduction of the information recorded on the disk.
Claim 7
Dependent Claim
35 words
Apparatus as claimed in any of claims 1 to 5 further including time base servo means (19) for correcting a time base error in the information recorded on the disk and detected by the pickup.
Claim 8
Dependent Claim
54 words
Apparatus as claimed in claim 6, further including a charge coupled device (17) having its output coupled to an input of the time base servo means (19) in a feedback manner, and a voltage-controlled oscillator (32) coupled between an output of the time base servo means and an input of the charge coupled device.
References Cited (Backward Citations)
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