System and apparatus for recovering information from a record currier which exhibits variations of two different physical parameters thereof
First Claim
1. An information system, comprising:
- a record carrier having information marks along a track thereof and exhibiting;
first variations caused by existence and non-existence of the information marks along the track, said first variations representing an information signal recorded on said record carrier, andsecond variations caused by variations associated with the track; and
a playback apparatus including;
transducer means for scanning said record carrier, said transducer means being adapted to detect said first variations and said second variations,recovery means coupled to said transducer means for recovering the information signal from said first variations,detection means for detecting whether said second variations exhibit a predetermined variation pattern on the basis of at least one signal, which is at least indicative of said second variations, originating from said transducer means, andenabling means for enabling said recovery means to recover the information signal when said detection means detects said predetermined variation pattern.
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Accused Products
Abstract
An information system including a record carrier and a playback apparatus. Information has been recorded on the record carrier in the form of variations of a first physical parameter. The playback apparatus scans the record carrier by means of a transducer which is responsive to the variations of the first physical parameter. An information recovering circuit recovers the information from a detection signal received from the transducer. The record carrier also exhibits second variations of a second physical parameter, which differs from the first physical parameter, but which second variations are of a type that are detectable by the transducer. A detection circuit detects the presence of the second variations or a predetermined property thereof (e.g., that they exhibit a predetermined variation pattern) on the basis of the detection signal received from the transducer. A circuit responsive to the detection circuit enables the information recovering circuit, when the presence of the second variations or a predetermined property of the second variations is detected, causing it to recover the information.
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Citations
25 Claims
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1. An information system, comprising:
a record carrier having information marks along a track thereof and exhibiting; first variations caused by existence and non-existence of the information marks along the track, said first variations representing an information signal recorded on said record carrier, and second variations caused by variations associated with the track; and a playback apparatus including; transducer means for scanning said record carrier, said transducer means being adapted to detect said first variations and said second variations, recovery means coupled to said transducer means for recovering the information signal from said first variations, detection means for detecting whether said second variations exhibit a predetermined variation pattern on the basis of at least one signal, which is at least indicative of said second variations, originating from said transducer means, and enabling means for enabling said recovery means to recover the information signal when said detection means detects said predetermined variation pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A playback apparatus for recovering an information signal from a record carrier exhibiting first variations caused by existence and non-existence of information marks along a track thereof, which first variations represent the information signal, and second variations caused by variations associated with the track, the apparatus comprising:
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transducer means for scanning said record carrier, said transducer means being adapted to detect said first variations and said second variations, recovery means coupled to said transducer for recovering the information signal from said first variations, detection means for detecting whether said second variations exhibit a predetermined variation pattern on the basis of at least one signal, which is at least indicative of said second variations, originating from said transducer means, and enabling means for enabling said recovery means to recover the information signal when said detection means detects said predetermined variation pattern. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A playback apparatus for recovering an information signal from a record carrier exhibiting at least first variations caused by existence and non-existence of information marks along a track thereof, which first variations represent the information signal, the apparatus comprising:
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transducer means for scanning said record carrier, said transducer means being adapted to detect said first variations; recovery means coupled to said transducer for recovering the information signal from said first variations, detection means for detecting whether said record carrier exhibits second variations caused by variations associated with the track, and enabling means for enabling said recovery means to recover the information signal when said detection means detects said second variations. - View Dependent Claims (23)
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24. A playback apparatus for recovering information from a record carrier exhibiting first variations of a first physical parameter of said record carrier corresponding to said information, and second variations of a second physical parameter of said record carrier, said first physical parameter and said second physical parameter differing from each other, the apparatus comprising:
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transducer means for scanning said record carriers, said transducer means being adapted to detect said first variations and said second variations and including a radiation sensitive detector and means for directing a radiation beam on said radiation detector via said record carrier, servo control means for controlling the scanning in order to control at least one scanning parameter to a predetermined value on the basis of an error signal, which is at least indicative of said second variations, originating from said transducer means, recovery means coupled to said transducer for recovering the information from said first variations, detection means for detecting whether said second variations exhibit a predetermined variation pattern on the basis of the error signal, and enabling means for enabling said recovery means to recover the information when said detection means detects said predetermined variation pattern.
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25. An information system, comprising:
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a record carrier of an optical readable type exhibiting; first variations of a first physical parameter of said record carrier, said first variations corresponding to information recorded on said record carrier as a pattern of optically detectable marks alternating with intermediate areas arranged along a track thereof, and second variations of a second physical parameter of said record carrier, said second physical parameter differing from said first physical parameter; a playback apparatus having; transducer means for scanning said record carrier, said transducer means being adapted to detect said first variations and said second variations, and including a radiation sensitive detector and means for directing a radiation beam on said radiation sensitive detector via said record carrier, recovery means coupled to said transducer for recovering the information from said first variations, detection means for detecting whether said second variations exhibit a predetermined variation pattern on the basis of at least one signal, which is at least indicative of said second variations, originating from said transducer means, and enabling means for enabling said recovery means to recover the information when said detection means detects said predetermined variation pattern; and servo control means for controlling the scanning in order to control at least one scanning parameter to a predetermined value, which servo control means operates on the basis of signal components within said at least one signal which are within a predetermined frequency bandwidth; wherein said second variations cause variations in said at least one signal which exhibit a frequency spectrum which is located outside the predetermined frequency bandwidth of operation of said servo control means and outside the frequency spectrum of said first variations.
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Specification