Koninklijke Philips Corporation N.v.

Paulus G P Weyenbergh

Jakob Gerrit Nijboer

Ronald Reindert Drenten

Johannes H M Spruit

Johannes J L M Van Vlerken

A record carrier ( ) is described comprising a servo track ( ) indicating an information track ( ) intended for recording information blocks represented by marks having lengths expressed in channel bits, which servo track ( ) has a periodic variation of a physical parameter. The periodic variation is modulated for encoding record carrier information, such as addresses. The modulation is a bi-phase modulation in which a data bit of the record carrier information is encoded by a first predetermined number of variations of a first phase followed by the same number of variations of a second phase inverse to the first phase. A recording and/or playback device has a demodulator for retrieving data bits of the record carrier information from a first predetermined number of variations of a first phase followed by the same number of variations of a second phase inverse to the first phase.

Record carrier and apparatus for scanning the record carrier

A record carrier is described comprising a servo track indicating an information track intended for recording information blocks represented by marks having lengths expressed in channel bits, which servo track has a periodic variation of a physical parameter. The periodic variation is modulated for encoding record carrier information, such as addresses. The modulation is a bi-phase modulation in which a data bit of the record carrier information is encoded by a first predetermined number of variations of a first phase followed by the same number of variations of a second phase inverse to the first phase. A recording and/or playback device has a demodulator for retrieving data bits of the record carrier information from a first predetermined number of variations of a first phase followed by the same number of variations of a second phase inverse to the first phase.

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Eindhoven, Netherlands

Paulus G P Weyenbergh