Record carrier and apparatus for scanning the record carrier

A recording and/or playback device comprising:

• a read-write device configured to write and/or read information blocks in an information track on a record carrier that comprises a servo track indicating the information track,
• a scanner configured to scan the servo track, and
• demodulator configured to retrieve record carrier information from a signal generated by a variation of a physical parameter of the servo track, wherein the servo track has:
• non-modulated parts having only said variation at a predetermined frequency, and
• modulated parts in which the frequency and/or phase of the variation deviates from the frequency and/or phase of the non-modulated parts for representing data bits of the record carrier information, and
• wherein the modulated parts comprise at least one variation of a phase inverse to the phase of the non-modulated periodic variations.

A recording and/or playback device comprising:

• a read-write device configured to write and/or read information blocks in an information track on a record carrier that comprises a servo track indicating the information track;
• a scanner configured to scan the servo track;
• and
• demodulator configured to retrieve record carrier information from a signal generated by a variation of a physical parameter of the servo track, wherein the servo track has:
• non-modulated parts having only said variation at a predetermined frequency, and
• modulated parts in which the frequency and/or phase of the variation deviates from the frequency and/or phase of the non-modulated parts for representing data bits of the record carrier information, and
• wherein at least one of the modulated parts comprises a variation at a second frequency, a length of said modulated part corresponding to m/2 periods of the predetermined frequency and corresponding to p/2 periods of the second frequency, n and p being different integers and being both odd or both even.

A method of manufacturing a record carrier comprising acts of:

• providing the record carrier with a servo track indicating an information track intended for recording information blocks;
• providing the servo track with a variation of a physical parameter at a predetermined frequency;
• modulating the variation for encoding record carrier information;
• and
• providing servo track with:
• non-modulated parts having only said variation at a predetermined frequency, and
• modulated parts in which the frequency and/or phase of the variation deviates from the frequency and/or phase of the non-modulated parts for representing data bits of the record carrier information;
• wherein the modulated parts comprise at least one variation of a phase inverse to the phase of the non-modulated periodic variations.

A method of manufacturing a record carrier comprising acts of:

• providing the record carrier with a servo track indicating an information track intended for recording information blocks;
• providing the servo track with a variation of a physical parameter at a predetermined frequency;
• modulating the variation for encoding record carrier information;
• and
• providing servo track with:
• non-modulated parts having only said variation at a predetermined frequency, and
• modulated parts in which the frequency and/or phase of the variation deviates from the frequency and/or phase of the non-modulated parts for representing data bits of the record carrier information;
• wherein at least one of the modulated parts comprises a variation at a second frequency, a length of said modulated part corresponding to m/2 periods of the predetermined frequency and corresponding to p/2 periods of the second frequency, n and p being different integers and being both odd or both even.