Patent EA-002457-B1 (EA)
Title: Record carrier, playback device and method of recording information
Inventor: SPRUIT JOHANNES H M
IPC: G11B7/24082
Filed: 2000-01-10
Abstract: 1. Record carrier comprising substantially parallel tracks exhibiting -first variations of a first physical parameter of the track, the first variations representing information recorded on the record carrier, which information is recoverable by means of a controllable type of data processing; and -second variations of a second physical parameter of the track, a modulation pattern of the second variations representing a code for controlling said type of data processing, characterized in that, in respect of a code track (42) that comprises the modulation pattern, the modulation pattern in the left neighbouring track (41) is aligned to the modulation pattern in the right neighbouring track (43). 2. Record carrier as claimed in claim 1, wherein the second variations are displacements of the track in a direction transverse to the longitudinal direction of the track, and displacements of the left neighbouring track coincide with displacements of the right neighbouring track in the same direction. 3. Record carrier as claimed in claim 1 or 2, wherein the modulation patterns in the code track and the neighbouring tracks represent the same code. 4. Record carrier as claimed in claim 3, wherein the modulation pattern in the code track (45) is substantially inverse to the modulation pattern in the left neighbouring track (44). 5. Record carrier as claimed in claim 3, wherein the second variations are periodic and the modulation pattern comprises phase modulation, and phase differences between modulation patterns in adjacent tracks are limited to a predetermined amount. 6. Record carrier as claimed in claim 1, wherein the tracks constitute a spiral or concentric pattern of tracks, and adjacent tracks in the pattern of tracks exhibit a same number of the second variations. 7. Record carrier as claimed in claim 1, wherein only tracks in a limited area (S1, S4) of the record carrier exhibit said second variations. 8. Record carrier as claimed in claim 7, wherein the limited area comprises a boundary zone (S1, S2) between an area not exhibiting second variations and a center area (S2, S3) exhibiting the second variations at a predetermined amplitude, in which boundary zone the amplitude of the second variations increases from zero to the predetermined amplitude. 9. Method of recording information on a record carrier, in which method the record carrier is provided with substantially parallel tracks, and the information is encoded in first variations of a first physical parameter of the track, which information is recoverable by means of a controllable type of data processing; and a code for controlling said type of data processing is encoded in a modulation pattern of second variations of a second physical parameter of the track, characterized in that, in respect of a code track that comprises the modulation pattern, the modulation pattern in the left neighbouring track is aligned to the modulation pattern in the right neighbouring track. 10. Method as claimed in claim 9, wherein the record carrier is rotated and the modulation pattern is generated in dependence on said rotation. 11. Playback device for recovering information from a record carrier as claimed in any one of the claims 1 to 8, the device comprising -reading means (52,53) for generating a read signal in dependence on the first variations, and -demodulation means (50) for retrieving the code from the modulation pattern of the second variations, and -data processing means (53) for processing the read signal for recovering the information in dependence on the code, characterized in that the device comprises means (56) for retrieving the code from at least two tracks. 12. Playback device as claimed in claim 11 for recovering information from a record carrier as claimed in claim 7, wherein the device comprises means (54,59) for locating the limited part.