Record carrier, playback apparatus and information system comprising a record carrier and a playback apparatus

Abstract

An information system according to the invention comprises a record carrier and a playback apparatus. The record carrier has information marks along a track thereof and exhibits first variations caused by existence and nonexistence of the information marks along the track. The first variations represent an information signal recorded on said record carrier. The record carrier further exhibits second variations caused by variations associated with the information marks. The phase of the second variations is coupled to the phase of the first variations.

The invention claimed is: 
     
       1. An information system, comprising: a record carrier ( 1 ) having information marks along a track ( 11 ) thereof and exhibiting:
 first variations caused by existence and nonexistence of the information marks along the track, said first variations representing an information signal recorded on said record carrier, and second variations (W) caused by variations associated with the information marks; the phase of the second variations being coupled to the phase of the first variations, 
 a playback apparatus ( 20 ) including: 
 a transducer unit ( 20 A,  20 B,  20 C) (20 A , 20 B , 20 C ) for scanning said record carrier ( 1 ), said  10  transducer unit being adapted to detect said first variations and said second variations, 
 a first recovery unit ( 22 ) coupled to the transducer unit ( 20 A,  20 B,  20 C) (20 A , 20 B , 20 C ) for recovering a clock signal (CL) from the first variations, 
 a second recovery unit ( 23 ) coupled to the transducer unit ( 20 A,  20 B,  20 C) (20 A , 20 B , 20 C ) for recovering an information signal (S out ) from the first variations, 
 a detection unit ( 24 ) fur for detecting whether said second variations exhibit a predetermined variation pattern on the basis of at least one signal (S A ), which is at least indicative of said second variations, originating from said transducer unit, the detection unit ( 24 ) using the said clock signal (CL) for detecting, and 
 an enabling unit ( 25 ) for enabling said second recovery unit ( 23 ) to recover the information signal (Sout) (S out ) when said detection unit ( 24 ) 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 unit includes a demodulation unit for recovering said code on the basis of said at least one signal, and an activation unit for activating said enabling unit when said code is recovered. 
     
     
       3. The system as claimed in  claim 2 , wherein the information signal recorded on said reword 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 he used for recovering the information signal, and said playback apparatus further includes a unit for setting said recovery unit in a mode in which the predetermined type of data processing is performed when the information signal is recovered. 
     
     
       4. A record carrier ( 1 ) having information marks along a track ( 11 ) thereof and exhibiting:
 first variations caused by existence and nonexistence of the information marks along the track, said first variations representing an information signal recorded on said record carrier, and second variations (W) caused by variations associated with the information marks; the phase of the second variations being coupled to the phase of the first variations. 
 
     
     
       5. A record carder according to  claim 4 , characterized in that the second variations have either a first or a second phase with respect to the first variations. 
     
     
       6. A record carrier according to  claim 5 , characterized in that first and the second phase differ with by 180 degrees. 
     
     
       7. A record carrier according to  claim 4 , characterized in that a predetermined variation pattern in die second variations allows sampling of said second variations at twice the frequency of said second variations. 
     
     
       8. A record carrier according to  claim 4 , characterized in that said second variation have a first and a second phase such that a predetermined relationship between said first and said second phase coincides to a start of frame. 
     
     
       9. A record carrier according to  claim 8 , characterized in that said predetermined relationship is a zero crossing. 
     
     
       10. A playback apparatus ( 20 ) including:
 a transducer unit ( 20   A ,  20   B ,  20   C ) for scanning a record carrier ( 1 ), said transducer unit being adapted to detect at least first and second variations, said first variations representing an information signal recorded on said record carrier, and second variations (W) caused by variations associated with the information marks; the phase of the second variations being coupled to the phase of the first variations, 
 a first recovery unit ( 22 ) coupled to the transducer unit ( 20 A,  20 B,  20 C) (20 A , 20 B , 20 C ) for recovering a clock signal (CL) from the first variations, 
 a second recovery unit ( 23 ) coupled to the transducer unit ( 20 A,  20 B,  20 C) (20 A , 20 B , 20 C ) for recovering an information signal (S out ) from the first variations, 
 a detection unit ( 24 ) for detecting whether said second variations exhibit a predetermined variation pattern on the basis of at least one signal (S A ), which is at least indicative of said second variations, originating from said transducer unit, the detection unit ( 24 ) using the said clock signal (CL) for detecting and 
 an enabling unit ( 5 ) (25) for enabling said second recovery unit ( 23 ) to recover the information signal (Sout) (S out ) when said detection unit detects ( 24 ) said predetermined variation pattern. 
 
     
     
       11. A playback apparatus according to  claim 10 , characterized in that said predetermined variation pattern allows sampling of said second variations at twice the frequency of said second variations. 
     
     
       12. A playback apparatus according to  claim 10 , characterized in that said second variation have a first and a second phase such that a predetermined relationship between said first and said second phase coincides to a start of frame. 
     
     
       13. A playback apparatus according to  claim 12 , characterized in that said predetermined relationship is a zero crossing. 
     
     
       14. A system as claimed in  claim 1 , characterized in that a predetermined variation pattern within said second variation allows sampling of said second variations at twice the frequency of said second variations. 
     
     
       15. A system as claimed in  claim 1 , characterized in that said second variations have a first and a second phase such that a predetermined relationship between said first and said second phase coincides to a start of frame. 
     
     
       16. A system as claimed in  claim 15 , characterized in that predetermined relationship is a zero crossing. 
     
     
       17. An information system, comprising:
 a record carrier (1) having information marks along a track (11) thereof and exhibiting: first variations caused by existence and nonexistence of the information marks along the track, said first variations representing an information signal on said record carrier, and second variations (W) caused by variations associated with the information marks; the phase of the second variations being coupled to the phase of the first variations,   a playback apparatus (20) including:   a transducer unit (20 A , 20 B , 20 C ) for scanning said record carrier (1), said transducer unit being adapted to detect said first variations and said second variations and to generate at least one signal (S A ), which is indicative of said second variations,   a first recovery unit (22) coupled to the transducer unit (20 A , 20 B , 20 C ) for recovering a clock signal (CL) from the first variations,   a second recovery unit (23) coupled to the transducer unit (20 A , 20 B , 20 C ) for recovering an information signal (S out ) from the first variations,   a detection unit (24) for detecting whether said second variations exhibit a predetermined variation pattern on the basis of said at least one signal (S A ) and said clock signal (CL) and   an enabling unit (25) for enabling said second recovery unit (23) to recover the information signal (S out ) when said detection unit detects (24) said predetermined variation pattern.   
     
     
       18. The system as claimed in claim 17, wherein said second variations exhibit a modulation pattern representing a code; and said detection unit includes a demodulation unit for recovering said code on the basis of said at least one signal (S A ), and an activation unit for activating said enabling unit when said code is recovered. 
     
     
       19. The system as claimed in claim 18, wherein the information signal recorded on said record carrier 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 a unit for setting said second recovery unit in a mode in which the predetermined type of data processing is performed when the information signal is recovered. 
     
     
       20. A record carrier (1) having information marks along a track (11) thereof and exhibiting:
 first variations caused by existence and nonexistence of the information marks along the track, said first variations representing an information signal on said record carrier, and   second variations (W) caused by variations associated with the information marks; the phase of the second variations being coupled to the phase of the first variations.   
     
     
       21. A record carrier according to claim 20, characterized in that the second variations have either a first predetermined phase or a second predetermined phase with respect to the phase of the first variations. 
     
     
       22. A record carrier according to claim 21, characterized in that first and the second predetermined phase differ by 180 degrees. 
     
     
       23. A record carrier according to claim 20, characterized in that the second variations are variations of the track position in a direction transverse to the track direction, thereby exhibiting track wobbles. 
     
     
       24. A record carrier according to claim 23, characterized in that the phase of the second variations is coupled to those of the first variations in that a predetermined number of wobbles corresponds to a predetermined number of channel bits represented by the first variations. 
     
     
       25. A record carrier according to claim 20, characterized in that the information signal has frames having frame syncs. 
     
     
       26. A record carrier according to claim 25, characterized in that a zero crossing of the second variations has a pre-defined phase relationship with the frame syncs. 
     
     
       27. A record carrier according to claim 20, characterized in that the information is scrambled and the second variations exhibit a modulation pattern representing a code, indicative of the scramble method. 
     
     
       28. A record carrier according to claim 20, characterized in that the information is encrypted and the second variations exhibit a modulation pattern representing a code, indicative of the encryption key. 
     
     
       29. A record carrier according to claim 20, which is optically readable. 
     
     
       30. A record carrier according to claim 20, wherein the information marks are optically detectable marks in the form of pits. 
     
     
       31. A playback apparatus (20) including:
 a transducer unit (20 A , 20 B , 20 C ) for scanning a record carrier (1), said transducer unit being adapted to detect first variations representing an information signal on said record carrier and second variations and to generate at least one signal (S A ), which is indicative of said second variations,   a first recovery unit (22) coupled to the transducer unit (20 A , 20 B , 20 C ) for recovering a clock signal (CL) from the first variations,   a second recovery unit (23) coupled to the transducer unit (20 A , 20 B , 20 C ) for recovering an information signal (S out ) from the first variations,   a detection unit (24) for detecting whether said second variations exhibit a predetermined variation pattern on the basis of said at least one signal (S A ) and said clock signal (CL) and   an enabling unit (25) for enabling said second recovery unit (23) to recover the information signal (S out ) when said detection unit detects (24) said predetermined variation pattern.   
     
     
       32. The apparatus as claimed in claim 31, wherein said detection unit includes a demodulation unit for recovering a code from a modulation pattern of said second variations on the basis of said at least one signal (S A ), and an activation unit for activating said enabling unit when said code is recovered. 
     
     
       33. The apparatus as claimed in claim 32, wherein the information signal recorded on said record carrier 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 a unit for setting said second recovery unit in a mode in which the predetermined type of data processing is performed when the information signal is recovered. 
     
     
       34. A playback apparatus according to claim 31, characterized in that, while in the record carrier the information is encrypted and the second variations exhibit a modulation pattern representing a code indicative of the encryption key, the playback apparatus is adapted for decrypting the information using said code. 
     
     
       35. A playback apparatus according to claim 31, characterized in that, while in the record carrier the information is scrambled and the second variations exhibit a modulation pattern representing a code indicative of the scramble method, the playback apparatus is adapted for descrambling the information using said code. 
     
     
       36. A playback apparatus according to claim 31, characterized in that the transducer unit is adapted for detecting wobbles as said second variations, said wobbles being variations of the track position in a direction transverse to the track direction. 
     
     
       37. A playback apparatus according to claim 36, characterized in that the playback apparatus comprises a frequency divider for generating an auxiliary clock signal (CLW) out of the clock signal (CL) in accordance with the phase of the second variations being coupled to the phase of the first variations by a predetermined number of wobbles corresponding to a predetermined number of channel bits represented by the first variations, which auxiliary clock signal is for detecting the second variations. 
     
     
       38. A playback apparatus according to claim 37, characterized in that the frequency divider has an input for receiving a signal (SYNC) which indicates the start of a frame. 
     
     
       39. A playback apparatus according to claim 38, in which the signal (SYNC) is used for re-synchronizing the auxiliary clock signal. 
     
     
       40. An information system, comprising:
 a record carrier having information marks along a track thereof and exhibiting: first variations resulting from information marks along the track, said first variations representing an information signal, and second variations resulting from variations associated with the information marks that are substantially independent of the information signal; the phase of the second variations being coupled to the phase of the first variations,   a playback apparatus including:   a transducer unit for scanning said record carrier, said transducer unit having a detector for detecting said first variations and said second variations,   a first recovery unit communicating with the transducer unit for recovering a clock signal from the first variations,   a second recovery unit communicating with the transducer unit for recovering the information signal from the first variations,   a detection unit for detecting whether said second variations include a predetermined variation pattern, the detecting depending on said clock signal, and   an enabling unit for controlling when said second recovery unit recovers the information signal depending on when said detection unit detects said predetermined variation pattern.   
     
     
       41. A playback apparatus including:
 a transducer unit for scanning a record carrier, said transducer unit having a detector for detecting first variations encoding an information signal and second variations substantially independent of the information signal,   a first recovery unit communicating with the transducer unit for recovering a clock signal from the first variations,   a second recovery unit communicating with the transducer unit for recovering the information signal from the first variations,   a detection unit for detecting whether said second variations include a predetermined variation pattern, the detecting depending on said clock signal, and   an enabling unit for controlling when said second recovery unit recovers the information signal depending on when said detection unit detects said predetermined variation pattern.