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US5483515A
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Apparatus and method for cancelling cross-talk in signals from optical data storage systems
Assignee: International Business Machines Corp
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Filing: 1994-09-16
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Granted: 1996-01-09
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Expires: 2014-09-16
Abstract
Abstract A system is disclosed for canceling cross-talk in a data read signal from an optical data storage medium. The system includes three AD converters for receiving read signals from three read sensors, and the read signals respectively represent data from a center data track and its two adjacent side data tracks on an optical data storage disk. The digitized signals are sent to a skew compensator to remove time skew between the signals. Then, the amplitudes represented by the side track signals are adjusted, and the adjusted side track signals are subtracted from the center track signal to cancel cross-talk in the center track signal which is attributable to data contained in the side data tracks. The center track signal is then equalized to account for the frequency response of the center track read sensor.
Inventors
- 👤 David C. Cheng
- 👤 Jerry E. Hurst, Jr.
- 👤 Radley W. Olson
- 👤 David A. Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:50
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/004; G11B7/005
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
212 words
In an optical data storage system having a data storage medium containing at least one inner data track, one outer data track, and a center data track therebetween, a light source for emitting at least one light beam toward the inner, outer, and center tracks, and respective inner, outer, and center light sensors for receiving reflections of the beam and generating respective inner, outer, and center readback signals in response thereto, an apparatus for generating a data signal representative of data in the center data track, comprising: a signal conditioner for receiving the inner, outer, and center readback signals, the signal conditioner including a skew compensator for removing time skew between the signals, the, signal conditioner also including a gain controller for adjusting the amplitudes of the inner and outer signals in proportion to predetermined contributions to the amplitude of the center signal caused by reflection of the beam from the inner and outer tracks, respectively; a signal adder for receiving the inner, outer, and center readback signals from the signal conditioner and subtracting the inner and outer readback signals from the center readback signal to generate an output signal; and an equalizer for receiving the output signal from the signal adder and equalizing the output signal to generate the data signal.
Claim 2
Dependent Claim
212 words
In an optical data storage system having a data storage medium containing at least one inner data track, one outer data track, and a center data track therebetween, a light source for emitting at least one light beam toward the inner, outer, and center tracks, and respective inner, outer, and center light sensors for receiving reflections of the beam and generating respective inner, outer, and center readback signals in response thereto, an apparatus for generating a data signal representative of data in the center data track, comprising: a signal conditioner for receiving the inner, outer, and center readback signals, the signal conditioner including a skew compensator for removing time skew between the signals, the, signal conditioner also including a gain controller for adjusting the amplitudes of the inner and outer signals in proportion to predetermined contributions to the amplitude of the center signal caused by reflection of the beam from the inner and outer tracks, respectively; a signal adder for receiving the inner, outer, and center readback signals from the signal conditioner and subtracting the inner and outer readback signals from the center readback signal to generate an output signal; and an equalizer for receiving the output signal from the signal adder and equalizing the output signal to generate the data signal.
Claim 3
Dependent Claim
57 words
The apparatus of claim 1, wherein the light beam includes inner, outer, and center beams respectively directed at the inner, outer, and center data tracks, and the apparatus further comprises inner, outer, and center analog-to-digital (AD) converters for respectively digitizing the inner, outer, and center readback signals and for sending the digitized signals to the skew compensator.
Claim 4
Dependent Claim
88 words
The apparatus of claim 2, wherein the skew compensator includes: inner, outer, and center data buffers for respectively receiving the digitized inner, outer, and center readback signals; and a sampling clock for establishing a frequency for sampling the outputs of the AD converters, such that the lengths of the data buffers are such that a leading edge of the center readback signal exits the center buffer at substantially the same time as leading edges of the inner and outer readback signals exit the inner and outer buffers, respectively.
Claim 5
Dependent Claim
26 words
The apparatus of claim 3, wherein the skew compensator further comprises a fine tuner for eliminating temporal differences between the inner, outer, and center readback signals.
Claim 6
Dependent Claim
36 words
The apparatus of claim 4, wherein the inner, outer, and center readback signals are simultaneously sent to the skew compensator, and the free tuner selectively adjusts the frequency for sampling the outputs of the AD converters.
Claim 7
Dependent Claim
35 words
The apparatus of claim 4, wherein the frequency for sampling has a constant period, and the free tuner establishes respective digitizing times at which the AD converters digitize the inner, outer, and center readback signals.
Claim 8
Dependent Claim
34 words
The apparatus of claim 4, wherein the frequency for sampling has a constant period, and the temporal difference between the signals as they exit the respective buffers is interpolatively determined by the fine tuner.
Claim 9
Independent Claim
154 words
A device for cancelling side data track contributions to an optical signal from a main data track, wherein each side track borders the main track and generates a respective side track optical signal, comprising: a respective sensor associated with each optical signal for generating respective electrical main data track and electrical side data track signals representative of the associated optical signals; a skew compensator for receiving the electrical data track signals and aligning the signals in time; a gain controller for adjusting the amplitudes of the electrical side data track signals in proportion to predetermined side data track contributions to the main data track signal; an adder for subtracting the electrical side data track signals from the electrical main data track signal and generating an output signal representative thereof; and an equalizer for receiving the output signal from the adder and modifying the output signal in accordance with the frequency of the output signal.
Claim 10
Independent Claim
154 words
A device for cancelling side data track contributions to an optical signal from a main data track, wherein each side track borders the main track and generates a respective side track optical signal, comprising: a respective sensor associated with each optical signal for generating respective electrical main data track and electrical side data track signals representative of the associated optical signals; a skew compensator for receiving the electrical data track signals and aligning the signals in time; a gain controller for adjusting the amplitudes of the electrical side data track signals in proportion to predetermined side data track contributions to the main data track signal; an adder for subtracting the electrical side data track signals from the electrical main data track signal and generating an output signal representative thereof; and an equalizer for receiving the output signal from the adder and modifying the output signal in accordance with the frequency of the output signal.
Claim 11
Dependent Claim
120 words
The device of claim 8, further comprising: a respective analog-to-digital (AD) converter associated with each electrical signal responsive to the side data track signals and to the main data track signal for providing digitized inner, outer, and center signals, and the skew compensator includes: inner, outer, and center data buffers for respectively receiving the digitized inner, outer, and center signals; and a sampling clock for establishing a frequency for sampling the outputs of the AD converters, wherein the lengths of the data buffers are established such that the leading edge of the center signal exits the center buffer at substantially the same time as the leading edges of the inner and outer signals exit the inner and outer buffers, respectively.
Claim 12
Dependent Claim
26 words
The device of claim 9, wherein the skew compensator further comprises a fine tuner for further eliminating temporal differences between the inner, outer, and center signals.
Claim 13
Dependent Claim
35 words
The device of claim 10, wherein the inner, outer, and center signals are simultaneously sent to the skew compensator, and the fine tuner selectively adjusts the frequency for sampling the outputs of the AD converters.
Claim 14
Dependent Claim
34 words
The device of claim 10, wherein the frequency for sampling has a constant period, and the free tuner establishes respective digitizing times at which the AD converters digitize the inner, outer, and center signals.
Claim 15
Dependent Claim
34 words
The device of claim 10, wherein the frequency for sampling has a constant period, and the temporal difference between the signals as they exit the respective buffers is interpolatively determined by the fine tuner.
Claim 16
Dependent Claim
156 words
For an optical data storage device, a method for removing components of a main data track signal attributable to cross-talk signals from side data tracks bordering the main data track, comprising the steps of: (a) receiving optical signals from the main data track and the side data tracks with respective sensors; (b) generating electrical data track signals including respective electrical main data track and electrical side data track signals representative of the associated optical signals; (c) receiving the electrical data track signals and aligning the electrical data track signals in time; (d) adjusting the amplitudes of the electrical side data track signals in proportion to predetermined cross-talk contributions to the main data track signal; (e) subtracting the electrical side data track signals from the electrical main data track signal and generating an output signal representative thereof; (f) receiving the output signal; and (g) modifying the output signal in accordance with the frequency of the output signal.
Claim 17
Dependent Claim
156 words
For an optical data storage device, a method for removing components of a main data track signal attributable to cross-talk signals from side data tracks bordering the main data track, comprising the steps of: (a) receiving optical signals from the main data track and the side data tracks with respective sensors; (b) generating electrical data track signals including respective electrical main data track and electrical side data track signals representative of the associated optical signals; (c) receiving the electrical data track signals and aligning the electrical data track signals in time; (d) adjusting the amplitudes of the electrical side data track signals in proportion to predetermined cross-talk contributions to the main data track signal; (e) subtracting the electrical side data track signals from the electrical main data track signal and generating an output signal representative thereof; (f) receiving the output signal; and (g) modifying the output signal in accordance with the frequency of the output signal.
Claim 18
Dependent Claim
45 words
The method of claim 14, wherein step (c) includes sending the electrical data track signals to respective buffers and establishing the length of the buffers such that the leading edges of the electrical data track signals exit the respective buffers in substantially the same period.
Claim 19
Dependent Claim
29 words
The method of claim 15, further comprising the step of fine tuning the electrical data track signals by eliminating any remaining temporal differences between the electrical data track signals.
Claim 20
Dependent Claim
193 words
An optical data storage system, comprising: an optical data storage medium containing at least one inner data track, one outer data track, and a center data track therebetween; a light source for emitting inner, outer, and center light beams respectively toward the inner, outer, and center tracks; respective inner, outer, and center light sensors for receiving reflections of the beams and generating respective inner, outer, and center signals in response thereto; a signal conditioner for receiving the inner, outer, and center signals, the signal conditioner including a skew compensator for removing time skew between the signals, the signal conditioner also including a gain controller for adjusting the amplitudes of the inner and outer signals in proportion to predetermined contributions to the amplitude of the center signal caused by reflection of the center beam from the inner and outer tracks, respectively; a signal adder for receiving the inner, outer, and center signals from the signal conditioner and subtracting the inner and outer signals from the center signal to generate an output signal; and an equalizer for receiving the output signal from the signal adder and equalizing the output signal to generate the data signal.
Claim 21
Dependent Claim
193 words
An optical data storage system, comprising: an optical data storage medium containing at least one inner data track, one outer data track, and a center data track therebetween; a light source for emitting inner, outer, and center light beams respectively toward the inner, outer, and center tracks; respective inner, outer, and center light sensors for receiving reflections of the beams and generating respective inner, outer, and center signals in response thereto; a signal conditioner for receiving the inner, outer, and center signals, the signal conditioner including a skew compensator for removing time skew between the signals, the signal conditioner also including a gain controller for adjusting the amplitudes of the inner and outer signals in proportion to predetermined contributions to the amplitude of the center signal caused by reflection of the center beam from the inner and outer tracks, respectively; a signal adder for receiving the inner, outer, and center signals from the signal conditioner and subtracting the inner and outer signals from the center signal to generate an output signal; and an equalizer for receiving the output signal from the signal adder and equalizing the output signal to generate the data signal.
Claim 22
Dependent Claim
33 words
The system of claim 17, further comprising inner, outer, and center analog-to-digital (AD) converters for respectively digitizing the inner, outer, and center signals and for sending the digitized signals to the skew compensator.
Claim 23
Dependent Claim
86 words
The system of claim 18, wherein the skew compensator includes: inner, outer, and center data buffers for respectively receiving the digitized inner, outer, and center signals; and a sampling clock for establishing a frequency for sampling the outputs of the AD converters, wherein the lengths of the data buffers are established such that the leading edge of the center signal exits the center buffer at substantially the same time as the leading edges of the inner and outer signals exit the inner and outer buffers, respectively.
Claim 24
Dependent Claim
25 words
The system of claim 19, wherein the skew compensator further comprises a fine tuner for eliminating temporal differences between the inner, outer, and center signals.
Claim 25
Dependent Claim
35 words
The system of claim 20, wherein the inner, outer, and center signals are simultaneously sent to the skew compensator, and the fine tuner selectively adjusts the frequency for sampling the outputs of the AD converters.
Claim 26
Dependent Claim
34 words
The system of claim 20, wherein the frequency for sampling has a constant period, and the free tuner establishes respective digitizing times at which the AD converters digitize the inner, outer, and center signals.
Claim 27
Dependent Claim
34 words
The system of claim 20, wherein the frequency for sampling has a constant period, and the temporal difference between the signals as they exit the respective buffers is interpolatively determined by the fine tuner.
References Cited (Backward Citations)
US3491351A
Cited
US3824623A
Cited
US4425636A
Cited
US4504939A
Cited
US4581728A
Cited
US4831613A
Cited
US4660191A
Cited
US4720825A
Cited
US4633455A
Cited
US5020044A
Cited
US5166914A
Cited
US5181161A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-01-08 | 1999-07-10 | 2000-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-08 | 2003-07-10 | 2004-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-08 | 2007-07-10 | 2008-01-09 | $7700.00 | Window Closed / Lapsed |