US5844871A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical disk track counting apparatus and method for improved track access
Assignee: NEC Corp
•
Filing: 1997-02-13
•
Granted: 1998-12-01
•
Expires: 2017-02-13
Abstract
Abstract To accurately count the tracks traversed on an optical disk, even in the presence of noise and eccentricity, a track-counting apparatus is provided, this apparatus having an edge-detection circuit that detects the edges of a track-crossing signal and generates an edge-crossing signal, a logical AND circuit that takes the logical AND of the edge-crossing signal and a mirror signal to generate an effective edge signal, a direction-discriminating circuit which switches the logic state of the track-crossing signal based on the direction of movement toward the target track, thereby generating a pulse-discriminating signal, a count pulse separating circuit which, based on this pulse-discriminating signal, separates the effective edge signal into a count-down signal and a count-up signal, and a track counter which counts the number of tracks traversed, based on both the count-down signal and the count-up signal which are generated by the count pulse separating circuit.
Inventors
- 👤 Etsuo Maezawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:29
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/085; G11B7/08505; G11B7/08541
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
267 words
A track-counting apparatus for an optical disk, comprising: an optical detecting head which detects light reflected from an optical disk, a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by a binary quantization of said tracking-error signal at a point of zero crossing of said tracking error signal; a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk; and a track counter connected to said second waveform-generating circuit and which counts a number of tracks traversed by a spot beam which strikes a surface of an optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, and wherein said track counter further comprises: an edge-detection circuit which detects an edge of said track-crossing signal and generates an edge-crossing signal; a logical product circuit which takes a logical product of said edge-crossing signal generated by said edge-detection circuit and said mirror signal, and generates an effective edge signal; and a counter for counting the number of tracks traversed by said spot beam, in response to said effective edge signal wherein said track counter further comprises a seek direction discriminating circuit which determines a seek direction of said head by judging from a target track and a current track position of said head.
Claim 2
Dependent Claim
267 words
A track-counting apparatus for an optical disk, comprising: an optical detecting head which detects light reflected from an optical disk, a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by a binary quantization of said tracking-error signal at a point of zero crossing of said tracking error signal; a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk; and a track counter connected to said second waveform-generating circuit and which counts a number of tracks traversed by a spot beam which strikes a surface of an optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, and wherein said track counter further comprises: an edge-detection circuit which detects an edge of said track-crossing signal and generates an edge-crossing signal; a logical product circuit which takes a logical product of said edge-crossing signal generated by said edge-detection circuit and said mirror signal, and generates an effective edge signal; and a counter for counting the number of tracks traversed by said spot beam, in response to said effective edge signal wherein said track counter further comprises a seek direction discriminating circuit which determines a seek direction of said head by judging from a target track and a current track position of said head.
Claim 3
Dependent Claim
311 words
A track-counting apparatus for an optical disk, comprising: an optical detecting head which detects light reflected from an optical disk, a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by a binary quantization of said tracking-error signal at a point of zero crossing of said tracking error signal; a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk; and a track counter connected to said second waveform-generating circuit and which counts a number of tracks traversed by a spot beam which strikes a surface of an optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, and wherein said track counter further comprises; an edge-detection circuit which detects an edge of said track-crossing signal and generates an edge-crossing signal; a logical product circuit which takes a logical product of said edge-crossing signal generated by said edge-detection circuit and said mirror signal, and generates an effective edge signal; and a counter for counting the number of tracks traversed by said spot beam, in response to said effective edge signal, wherein said track counter further comprises a seek direction discriminating circuit which determines a seek direction of said head by judging from a target track and a current track position of said head, and wherein said track counter further comprises a direction discriminating circuit connected to said first waveform-generating circuit and said seek direction discriminating circuit and which generates a pulse-discriminating signal from said track-crossing signal in response to an output of said seek direction discriminating circuit.
Claim 4
Dependent Claim
311 words
A track-counting apparatus for an optical disk, comprising: an optical detecting head which detects light reflected from an optical disk, a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by a binary quantization of said tracking-error signal at a point of zero crossing of said tracking error signal; a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk; and a track counter connected to said second waveform-generating circuit and which counts a number of tracks traversed by a spot beam which strikes a surface of an optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, and wherein said track counter further comprises; an edge-detection circuit which detects an edge of said track-crossing signal and generates an edge-crossing signal; a logical product circuit which takes a logical product of said edge-crossing signal generated by said edge-detection circuit and said mirror signal, and generates an effective edge signal; and a counter for counting the number of tracks traversed by said spot beam, in response to said effective edge signal, wherein said track counter further comprises a seek direction discriminating circuit which determines a seek direction of said head by judging from a target track and a current track position of said head, and wherein said track counter further comprises a direction discriminating circuit connected to said first waveform-generating circuit and said seek direction discriminating circuit and which generates a pulse-discriminating signal from said track-crossing signal in response to an output of said seek direction discriminating circuit.
Claim 5
Dependent Claim
67 words
A track-counting apparatus for an optical disk according to claim 2, wherein said track counter further comprises a count pulse separating circuit connected to said logical product circuit and said direction discriminating circuit and which separates said effective edge signal into a count-down signal and count-up signal, in response to said pulse-discriminating signal output from said direction discriminating circuit so as to be supplied to said counter.
Claim 6
Independent Claim
249 words
A method for counting a number of tracks for an optical disk utilizing a track-counting apparatus comprising an optical detecting head which detects light reflected from an optical disk, a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by binary quantization of said tracking-error signal, a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk and a track counter connected to said second waveform-generating circuit and which counts the number of tracks traversed by a spot beam which strikes a surface of the optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, wherein said method comprises the steps; generating an edge-crossing signal by detecting an edge of a track-crossing signal; generating an effective edge signal by taking the logical product of said edge-crossing signal and said mirror signal; separating said effective edge signal into a count-down signal and a count-up signal, in response to information representing a seek-direction of said optical head; and counting a number of tracks traversed by said head in a radial direction of said optical disk utilizing at least one of said count-down signal and said count-up signal.
Claim 7
Independent Claim
249 words
A method for counting a number of tracks for an optical disk utilizing a track-counting apparatus comprising an optical detecting head which detects light reflected from an optical disk, a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by binary quantization of said tracking-error signal, a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk and a track counter connected to said second waveform-generating circuit and which counts the number of tracks traversed by a spot beam which strikes a surface of the optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, wherein said method comprises the steps; generating an edge-crossing signal by detecting an edge of a track-crossing signal; generating an effective edge signal by taking the logical product of said edge-crossing signal and said mirror signal; separating said effective edge signal into a count-down signal and a count-up signal, in response to information representing a seek-direction of said optical head; and counting a number of tracks traversed by said head in a radial direction of said optical disk utilizing at least one of said count-down signal and said count-up signal.
References Cited (Backward Citations)
JPS6360449A
Cited
US5184338A
Cited
JPH01277332A
Cited
US5193081A
Cited
US5426625A
Cited
JPH0793765A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-11-30 | 2002-06-01 | 2002-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-11-30 | 2006-06-01 | 2006-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-11-30 | 2010-06-01 | 2010-12-01 | $7700.00 | Window Closed / Lapsed |