System and apparatus for recovering information from a record currier which exhibits variations of two different physical parameters thereof

• US 5,737,286 A
• Filed: 02/15/1995
• Issued: 04/07/1998
• Est. Priority Date: 12/02/1991
• Status: Expired due to Term

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Schylander, Erik C., Mons, Johannes J., Timmermans, Jozef M. K.
• Primary Examiner(s): YOUNG, WAYNE R
• Application Number:
  US08/389,445
• Time in Patent Office: 1,147 Days
• Field of Search: 369/47-48, 369/53-54, 369/58, 369/44.13, 369/44.26, 369/275.3-275.4, 369/44.39, 369/100, 369/109, 369/111, 369/124, 360/133
• US Class Current: 369/44.13
• CPC Class Codes: G11B 13/00 Recording simultaneously or selectively by methods covered by different main groups among G11B3/00, G11B5/00, G11B7/00 and G11B9/00; Record carriers therefor not otherwise provided for; Reproducing therefrom not otherwise provided for G11B9/14, G11B11/002 take precedence; driving or moving of heads G11B3/02, G11B5/48, G11B7/08, G11B21/02
• CPC Class Codes: G11B 19/04 Arrangements for preventing, inhibiting, or warning against double recording on the same blank or against other recording or reproducing malfunctions
• CPC Class Codes: G11B 19/12 by sensing distinguishing features of or on records, e.g. diameter end mark
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00405 the key being stored by varying characteristics of the recording track, e.g. by altering the track pitch or by modulating the wobble track
• CPC Class Codes: G11B 20/00586 said format change concerning the physical format of the recording medium
• CPC Class Codes: G11B 20/00594 wherein the shape of recording marks is altered, e.g. the depth, width, or length of pits
• CPC Class Codes: G11B 20/00601 wherein properties of tracks are altered, e.g., by changing the wobble pattern or the track pitch, or by adding interruptions or eccentricity
• CPC Class Codes: G11B 20/1809 by interleaving
• CPC Class Codes: G11B 23/281 by changing the physical properties of the record carrier
• CPC Class Codes: G11B 23/284 on the record carrier
• CPC Class Codes: G11B 5/02 Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
• CPC Class Codes: G11B 5/74 Record carriers characterised by the form, e.g. sheet shaped to wrap around a drum
• CPC Class Codes: G11B 7/0037 with discs
• CPC Class Codes: G11B 7/005 Reproducing G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/00736 Auxiliary data, e.g. lead-in, lead-out, Power Calibration Area [PCA], Burst Cutting Area [BCA], control information sector headers or adresses in prepits G11B7/00745; address data in track wobble G11B7/24082
• CPC Class Codes: G11B 7/0901 for track following only G11B7/0925, G11B7/094, G11B7/0941, G11B7/0943, G11B7/0945, G11B7/0946, G11B7/0948 take precedence
• CPC Class Codes: G11B 7/0938 servo format, e.g. guide tracks, pilot signals
• CPC Class Codes: G11B 7/24085 Pits
• CPC Class Codes: G11B 9/00 : Recording or reproducing using a method not covered by one of the main groups G11B3/00 - G11B7/00; Record carriers therefor G11B11/00 takes precedence driving or moving of heads G11B21/02
• CPC Class Codes: H04N 2005/91342 : the copy protection signal being an authentication signal
• CPC Class Codes: H04N 2005/91364 : the video signal being scrambled
• CPC Class Codes: H04N 5/913 : for scrambling ; for copy protection

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.

Claims

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.

2. The system as claimed in claim 1, wherein said second variations exhibit a modulation pattern representing a code;

and said detection means includes demodulation means for recovering said code on the basis of said at least one signal, and activation means for activating said enabling means when said code is recovered.

3. The system as claimed claim 2, wherein the information signal recorded on said record carrier is of a type which is recoverable by means of a predetermined type of data processing, said code indicating the predetermined type of data processing to be used for recovering the information signal, and said playback apparatus further includes means for setting said recovery means in a mode in which the predetermined type of data processing is performed when the information signal is recovered.

4. The system as claimed in claim 1, wherein said record carrier is of an optical readable type in which the existence and non-existence of the information marks along the track correspond to a pattern of optically detectable information marks alternating with intermediate areas arranged along the track and said transducer means includes a radiation sensitive detector, and means for directing a radiation beam on said radiation sensitive detector via said record carrier.

5. The information system as claimed in claim 4, further comprising servo control means for controlling the scanning in order to control at least one scanning parameter to a predetermined value, said servo control means operating 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.

6. The system as claimed in claim 5, wherein said servo control means includes tracking control means for controlling tracking, and said second variations are caused by variations in the track position in a direction transverse to the track direction.

7. The information system as claimed in claim 6, wherein said record carrier is a Compact Disc, and said second variations result in variations in said at least one signal with a frequency substantially corresponding to 22 kHz when the track is scanned with a scanning speed between 1.2 to 1.4 meter per second.

8. The system as claimed in claim 5, wherein said servo control means includes focus control means for maintaining a focal point of a scanning beam used to scan said record carrier substantially in the plane in which said optically detectable information marks and intermediate areas are located, and said second variations are caused by variations in the position of said plane.

9. The system as claimed in claim 1, wherein said second variations exhibit a modulation pattern representing a code, said detection means includes demodulation means for recovering said code on the basis of said at least one signal, and said enabling means enables said recovery means to recover the information signal when said code is a predetermined code.

10. The system as claimed in claim 9, wherein the information signal recorded on said record carrier is of a type which is recoverable by means of a predetermined type of data processing, said code being the predetermined code and indicating the predetermined type of data processing to be used for recovering the information signal, and said playback apparatus further includes means for setting said recovery means in a mode in which the predetermined type of data processing is performed when the information signal is recovered.

11. The system as claimed in claim 1, wherein the information signal recorded on said record carrier is of a type which is recoverable by means of a predetermined type of data processing, said second variations exhibit a modulation pattern representing a code indicating the predetermined type of data processing to be used for recovering the information signal, said detection means includes demodulation means for recovering said code on the basis of said at least one signal, and said playback apparatus further includes means for setting said recovery means in a mode in which the predetermined type of data processing is performed during recovery of the information signal.

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:

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.

13. The apparatus as claimed in claim 12, wherein said second variations exhibit a modulation pattern representing a code;

and said detection means includes demodulation means for recovering said code on the basis of said at least one signal, and activation means for activating said enabling means when said code is recovered.

14. The apparatus as claimed in claim 13, further comprising means for setting said recovery means in a mode in which a predetermined type of data processing indicated by said code is performed when the information signal is recovered.

15. The apparatus as claimed in claim 12, wherein said transducer means includes a radiation sensitive detector, and means for directing a radiation beam on said radiation sensitive detector via said record carrier.

16. The apparatus as claimed in claim 15, further comprising 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 derived from said at least one signal, and wherein said detection means detects whether said second variations exhibit the predetermined variation pattern on the basis of said error signal.

17. The apparatus as claimed in claim 16, wherein said servo control means includes tracking control means for controlling tracking on the basis of a tracking error signal derived from said at least one signal.

18. The apparatus as claimed in claim 16, wherein said record carrier is of an optical readable type in which the existence and non-existence of the information marks along the track correspond to a pattern of optically detectable information marks alternating with intermediate areas arranged along the track, and said servo control means includes focus control means for maintaining a focal point of a scanning beam used to scan said record carrier substantially in the plane in which said optically detectable information marks and intermediate areas are located on the basis of a focus error signal derived from said at least one signal.

19. The apparatus as claimed in claim 12, wherein said second variations exhibit a modulation pattern representing a code, said detection means includes demodulation means for recovering said code on the basis of said at least one signal, and the apparatus further comprises means for setting said recovery means in a mode in which a predetermined type of data processing indicated by said code is performed during recovery of the information signal.

20. The apparatus as claimed in claim 12, wherein said second variations exhibit a modulation pattern representing a code, said detection means includes demodulation means for recovering said code on the basis of said at least one signal, and said enabling means enables said recovery means to recover the information signal when said code is a predetermined code.

21. The apparatus as claimed in claim 20, wherein said code is said predetermined code, and the apparatus further comprises means for setting said recovery means in a mode in which a predetermined type of data processing indicated by said code is performed during recovery of the information signal.

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:

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.

23. The apparatus as claimed in claim 22, wherein said second variations exhibit a modulation pattern representing a code, said detection means includes demodulation means for recovering said code on the basis of said at least one signal, and the apparatus further comprises means for setting said recovery means in a mode in which a predetermined type of data processing indicated by said code is performed during recovery of the information signal.

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:

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.

25. An information system, comprising:

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.