Record carrier, playback device and method of recording information

Abstract

A record carrier has substantially parallel tracks having first variations of a first physical parameter and second variations of a second physical parameter of the track. The first variations represent information recorded on the record carrier, this information being recoverable by a controllable type of data processing. A modulation pattern of the second variations represents a code for controlling the type of data processing. In respect of a code track that includes the modulation pattern, the modulation pattern in the left neighboring track is aligned to the modulation pattern in the right neighboring track. Thereby crosstalk due to the second variations is decreased, and at least two tracks have the same modulation pattern. The playback device has a demodulator (50) and a control unit (56) for retrieving the code from at least two tracks.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is a reissue application of patent U.S. Pat. No. 7,054,245 which issued on May 30, 2006 from an application Ser. No. 10 / 382,674, filed Mar. 6, 2003, which is a continuation of U.S. patent application Ser. No. 09 / 488,027, filed Jan. 20, 2000, now U.S. Pat. No. 6,549,495 which issued on Apr. 15, 2003, and which claims foreign priority from EP 99200217.0, filed Jan. 27, 1999.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to a record carrier comprising substantially parallel tracks having first variations of a first physical parameter of the track, the first variations representing information recorded on the record carrier, the information being recoverable by 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.[0004]The invention furt...

AI Technical Summary

Benefits of technology

The invention is about a record carrier and a playback device that use aligned modulation patterns in neighboring tracks to reduce crosstalk and maintain track tolerances. The second variations in the modulation patterns in neighboring tracks are aligned to compensate for any increase in disturbance caused by a second variation in the left neighboring track. The amplitude of the second variations must be low to prevent noise and errors in the detected information. The invention also recognizes that the second variations are displacements of the track in a direction transverse to the longitudinal direction of the track, which reduces crosstalk between adjacent tracks. The modulation patterns in the code track and neighboring tracks represent the same code, and the distance between the tracks remains the same, which strengthens the detection signal of the code track. The second variations are periodic, and the modulation pattern in the neighboring track is in phase with the read signal from the code track. The playback device comprises means for retrieving the code from at least two tracks, and the code is verified by reading a further track carrying the same code, which makes the retrieval more reliable.

Problems solved by technology

Therefore, the tight tolerances on the parameters of the track can effectively be maintained and crosstalk remains limited to acceptable values.

However, in a high-density record carrier, the modulation of the second variations in neighboring tracks causes crosstalk, and, therefore, causes noise which degrades the detection of the recorded information and detection of the modulation pattern itself.

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