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

A playback apparatus (20) including:

• a transducer unit (20A, 20B, 20C) 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 (20A, 20B, 20C) (20A, 20B, 20C) for recovering a clock signal (CL) from the first variations,
• a second recovery unit (23) coupled to the transducer unit (20A, 20B, 20C) (20A, 20B, 20C) for recovering an information signal (Sout) 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 (SA), 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) (Sout) when said detection unit detects (24) said predetermined variation pattern.

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 (20A, 20B, 20C) 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 (SA), which is indicative of said second variations,
• a first recovery unit (22) coupled to the transducer unit (20A, 20B, 20C) for recovering a clock signal (CL) from the first variations,
• a second recovery unit (23) coupled to the transducer unit (20A, 20B, 20C) for recovering an information signal (Sout) 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 (SA) and said clock signal (CL) and
• an enabling unit (25) for enabling said second recovery unit (23) to recover the information signal (Sout) when said detection unit detects (24) said predetermined variation pattern.

A playback apparatus (20) including:

• a transducer unit (20A, 20B, 20C) 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 (SA), which is indicative of said second variations,
• a first recovery unit (22) coupled to the transducer unit (20A, 20B, 20C) for recovering a clock signal (CL) from the first variations,
• a second recovery unit (23) coupled to the transducer unit (20A, 20B, 20C) for recovering an information signal (Sout) 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 (SA) and said clock signal (CL) and
• an enabling unit (25) for enabling said second recovery unit (23) to recover the information signal (Sout) when said detection unit detects (24) said predetermined variation pattern.

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.

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.