EP0325434A2
Expired / Lapsed
EP
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Track access control system
Assignee: Fujitsu Ltd
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Filing: 1989-01-18
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Granted: —
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Expires: 2009-01-18
Abstract
Abstract A track access control system for a disc storage system having an eccentricity correction unit. The eccentricity correction unit includes an eccentricity detecting unit (29), an eccentricity data storage unit (70) and an eccentricity compensation unit (3). The eccentricity data storage unit includes a memory (70), an address generating circuit (73), a filter (74) and a comparator (75). The comparator (75) and the filter (74) function as a delta modulation means to provide a digital eccentricity data to be stored in the memory. The filter also outputs analogue eccentricity data to be used for compensation of the eccentricity.
Inventors
- 👤 Shigeyoshi Tanaka
- 👤 Shigenori Yanagi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 07:17
CPC Classifications
G; G11; G11B; G11B25/00; G11B25/04; G11B7/00; G11B7/08; G11B7/085; G11B7/08505; G11B7/08517; G11B21/00; G11B21/02; G11B21/08; G11B21/081; G11B21/083; G11B21/085; G11B7/09; G11B7/095; G11B7/0953
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
404 words
A track access control system for use in a disc storage system including a rotatable recording disc (1) on which a plurality of tracks, to which data is recorded and from which data is read, are formed along a rotation direction of the rotatable disc, a data recording and reading head (2) which is movable in a radial direction across the disc, a track actuator means (6) for moving the head in a radial direction relative to the disc, and a track error sensor (29) for detecting a track error signal in response to a signal read through the head, the system comprising a track servo control means (3), operatively connected to the track error signal sensor (29) and the track actuator means (6), for positioning the head (2) at a desired position through the track actuator means in response to the track error signal from the track error sensor; and an eccentricity correction means, operatively connected to the track error sensor, and operatively connected to the track servo control means to cooperate therewith, for detecting an eccentricity of the tracks at a first condition, storing the eccentricity, and compensating the eccentricity of the track together with the track servo control means at a second condition after the first condition, the eccentricity correction means including, an eccentricity detecting means for detecting the eccentricity in response to a deviation of the track for at least a half rotation of the disc, an eccentricity wave signal storage means (7) having a memory (70), an address generation circuit (73), a filter (74) connected to an output of the memory, and a comparator (75) having an input connected to an output of the filter, another input thereat connected to the eccentricity detecting means (29) to receive the eccentricity data, and an output thereof connected to an input of the memory (70), the address generation circuit generating an address signal for the memory in response to a rotation of the disc, the filter reproducing an analogue reproduction eccentricity wave signal in response to data stored in the memory, the comparator comparing the analogue reproduction eccentricity wave signal with the received eccentricity and outputting digital data indicating a polygonal line shaped sinusoidal eccentricity signal, and an eccentricity compensation means for receiving the analogue reproduction eccentricity wave signal from the filter (24) and adding the received reproduction eccentricity wave signal to the track error signal so that the eccentricity is compensated.
Claim 2
Dependent Claim
404 words
A track access control system for use in a disc storage system including a rotatable recording disc (1) on which a plurality of tracks, to which data is recorded and from which data is read, are formed along a rotation direction of the rotatable disc, a data recording and reading head (2) which is movable in a radial direction across the disc, a track actuator means (6) for moving the head in a radial direction relative to the disc, and a track error sensor (29) for detecting a track error signal in response to a signal read through the head, the system comprising a track servo control means (3), operatively connected to the track error signal sensor (29) and the track actuator means (6), for positioning the head (2) at a desired position through the track actuator means in response to the track error signal from the track error sensor; and an eccentricity correction means, operatively connected to the track error sensor, and operatively connected to the track servo control means to cooperate therewith, for detecting an eccentricity of the tracks at a first condition, storing the eccentricity, and compensating the eccentricity of the track together with the track servo control means at a second condition after the first condition, the eccentricity correction means including, an eccentricity detecting means for detecting the eccentricity in response to a deviation of the track for at least a half rotation of the disc, an eccentricity wave signal storage means (7) having a memory (70), an address generation circuit (73), a filter (74) connected to an output of the memory, and a comparator (75) having an input connected to an output of the filter, another input thereat connected to the eccentricity detecting means (29) to receive the eccentricity data, and an output thereof connected to an input of the memory (70), the address generation circuit generating an address signal for the memory in response to a rotation of the disc, the filter reproducing an analogue reproduction eccentricity wave signal in response to data stored in the memory, the comparator comparing the analogue reproduction eccentricity wave signal with the received eccentricity and outputting digital data indicating a polygonal line shaped sinusoidal eccentricity signal, and an eccentricity compensation means for receiving the analogue reproduction eccentricity wave signal from the filter (24) and adding the received reproduction eccentricity wave signal to the track error signal so that the eccentricity is compensated.
Claim 3
Dependent Claim
69 words
A track access control system according to claim 1, wherein the memory (70) comprises a random access memory in which the eccentricity is stored only during the first condition and from which the eccentricity is read only during the second condition, and wherein the address generation circuit (73) comprises counter means receiving a rotation signal and generating the address for the memory (70) in response to the rotation signal.
Claim 4
Dependent Claim
41 words
A track access control system according to claim 1 or claim 2, further comprising wherein a clock generator which generates a rotation signal in the form of a clock signal, the clock signal being used for driving the rotatable recording disc.
Claim 5
Dependent Claim
35 words
A track access control system according to any of the preceding claims, wherein the filter (74) comprises a resistor and a capacitor, the resistor and the capacitor being connected to form a first-order delay circuit.
Claim 6
Dependent Claim
58 words
A track access control system according to any of the preceding claims, wherein the eccentricity correction means further comprises a controllable eccentricity detecting means for detecting a controllable eccentricity data for at least a half rotation of the disc, the controllable eccentricity data falling in a following range of the light beams throughout all tracks of the disc.
Claim 7
Dependent Claim
29 words
A track access control system according to claim 5, wherein the controllable eccentricity detecting means detects an optimum controllable eccentricity data falling in the centre of the following range.
Claim 8
Dependent Claim
156 words
A track access control system according to claim 6, wherein the controllable eccentricity detecting means comprises deviation detecting means for detecting a deviation of the eccentricity data for at least a half rotation of the disc from the eccentricity data stored in the memory (70), track skip means, operatively connected to the deviation detecting means, for skipping the head through the track actuator means by the detected deviation, eccentricity detecting and updating means for detecting eccentricity data adjusted by the skip operation of the head, and updating the detected eccentricity data to the eccentricity wave signal storage means in a polygonal line shaped sinusoidal eccentricity signal, and optimum eccentricity detection control means for detecting the optimum eccentricity for at least a half rotation of said disc and controlling operations of the deviation detecting means, the track skip means and the eccentricity detecting and updating means to sequentially continue those operations until the optimum eccentricity is detected.
Claim 9
Dependent Claim
33 words
A track access control system according to claim 7, wherein the detection of said eccentricity and/or the detection of said optimum eccentricity data are carried out at one full rotation of the disc.
Claim 10
Dependent Claim
44 words
A track access control system according to claim 8, when dependent on claim 2, wherein the optimum eccentricity data are stored in the memory only during the first condition and the optimum eccentricity data are read from the memory only during the second condition.
Claim 11
Dependent Claim
67 words
A track access control system according to any of the preceding claims, wherein the track actuator means (6) comprises a first moving unit, and a second moving unit mounted on the first moving unit, the first moving unit moving the head more than one track, and the second moving unit finely moving said head at the track after completion of the movement of the first moving unit.
Claim 12
Dependent Claim
110 words
A signal storage system comprising a memory (70); an address generation circuit (73); a filter (74) connected to an output of the memory; and a comparator (75) having an input connected to an output of the filter, another input receiving an analogue input signal, and an output thereof connected to an input of the memory, the address generation circuit (73) generating an address signal for the memory in response to a clock signal, the filter (74) reproducing an analogue reproduction signal in response to data stored in the memory; and the comparator (75) comparing the analogue reproduction signal with the analogue input signal and outputting digital data to the memory.
Claim 13
Dependent Claim
110 words
A signal storage system comprising a memory (70); an address generation circuit (73); a filter (74) connected to an output of the memory; and a comparator (75) having an input connected to an output of the filter, another input receiving an analogue input signal, and an output thereof connected to an input of the memory, the address generation circuit (73) generating an address signal for the memory in response to a clock signal, the filter (74) reproducing an analogue reproduction signal in response to data stored in the memory; and the comparator (75) comparing the analogue reproduction signal with the analogue input signal and outputting digital data to the memory.
Claim 14
Dependent Claim
27 words
A signal storage system according to claim 11, wherein the input analogue signal comprises a sinusoidal wave, and the filter (74) reproduces the analogue sinusoidal reproduction signal.
Claim 15
Dependent Claim
34 words
A signal storage system according to claim 11 or claim 12, wherein the filter (74) comprises a resistor and a capacitor, the resistor and the capacitor being connected to form a first-order delay circuit.
Claim 16
Dependent Claim
77 words
A signal storage system according to any of claims 11 to 13, wherein the memory (70) comprises a random access memory in which the analogue input signal is stored only during a first condition and from which the data is read only during a second condition after the first condition, and wherein the address generation circuit (73) comprises counter means receiving the clock signal and generating the address for the memory in response to the clock signal.
References Cited (Backward Citations)
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