Patent EP0362987A2 successfully refreshed from Google Patents.
EP0362987A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Servo device for disc player
Assignee: Pioneer Corp
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Filing: 1989-07-12
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Granted: —
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Expires: 2009-07-12
Abstract
Abstract A disk player having digital processing of error signals (FE,TE) in a servo system utilizes an A/D converter (12). 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 (12), and the coverter (12) output representating the digitized small error signals is 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 (12) input to permit the same A/D converter (12) to convert both the open loop and the closed loop error signals faithfully.
Inventors
- 👤 Hidehiro Pioneer Electronic Corporation Ishii
- 👤 Noriyoshi Pioneer Electronic Corporation Takeya
- 👤 Chiharu Pioneer Electronic Corporation Miura
- 👤 Tatsuya Pioneer Electronic Corporation Fukuda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 20:41
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0941
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
177 words
A disk player servo device comprising: an A/D converter (2) for digitizing at least one analog error signal (FE,TE) formed from an output signal of a pickup adapted to read data from a disk; means for driving the pickup according to the level of the error signal (FE,TE); a variable gain amplifier (9,10) provided on the input side of the A/D converter (12) for amplifying the at least one error signal (FE,TE) and supplying the amplified error signal to the A/D converter (2); digital signal variable amplification means (13) connected to receive the digitized output signals from the A/D converter (2); and, control means (15,18) connected to the variable gain amplifier (9,10) and the variable amplification means (13) and responsive to the open/closed loop condition of the servo for controlling the amplification factors of the amplifier (9,10) and amplification (13) means to achieve substantially equal overall gain for both open loop and closed loop error signals while greatly increasing the voltage range of the at least one closed loop error signal input to the A/D converter (12).
Claim 2
Dependent Claim
177 words
A disk player servo device comprising: an A/D converter (2) for digitizing at least one analog error signal (FE,TE) formed from an output signal of a pickup adapted to read data from a disk; means for driving the pickup according to the level of the error signal (FE,TE); a variable gain amplifier (9,10) provided on the input side of the A/D converter (12) for amplifying the at least one error signal (FE,TE) and supplying the amplified error signal to the A/D converter (2); digital signal variable amplification means (13) connected to receive the digitized output signals from the A/D converter (2); and, control means (15,18) connected to the variable gain amplifier (9,10) and the variable amplification means (13) and responsive to the open/closed loop condition of the servo for controlling the amplification factors of the amplifier (9,10) and amplification (13) means to achieve substantially equal overall gain for both open loop and closed loop error signals while greatly increasing the voltage range of the at least one closed loop error signal input to the A/D converter (12).
Claim 3
Dependent Claim
50 words
A servo device according to claim 1, wherein the control means (15,18) controls the amplification factor of the amplifier (9,10) so that it has a gain of G₁ when the servo loop is open and a gain of NG₁ when the servo loop is closed, and where N > 1.
Claim 4
Dependent Claim
42 words
A servo device according to claim 2, wherein the control means (15,18) controls the amplification means (13) so that it has a gain of G₂ when the servo loop is open and a gain of G₂/N when the servo loop is closed.
Claim 5
Dependent Claim
19 words
A servo device according to any of claims 1 to 3, wherein the control means (15,18) comprises a microcomputer.
Claim 6
Dependent Claim
33 words
A servo device according to any of claims 1 to 4, wherein the amplification means is a digital equalizer (13) for compensating the frequency characteristic of the at least one error signal (FE,TE).
Claim 7
Dependent Claim
21 words
A servo device according to any of claims 1 to 5, wherein the error signal is a tracking error signal (TE).
Claim 8
Dependent Claim
21 words
A servo device according to any of claims 1 to 5, wherein the error signal is a focus error signal (FE).
References Cited (Backward Citations)
No citation records indexed.
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