Rewritable optical recording medium and methods of recording EFM-modulated information on the record

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The invention relates to an optical disc recording/retrieving apparatus comprising a motor (M1) for rotating a disc (D1). The disc has a spiral groove (105) with wobble, address information identifying each recording data block, which is a unit of recording information located at a specified position in the spiral groove (105), a synchronization pattern identifying a head position of the recording data block, and a recording layer. The apparatus further comprises, among others, an optical pick-up (PU1) for generating a focused laser beam irradiating the disc (D1), a groove tracking servo circuit (TE1) for scanning the spiral groove, a detector and decoder circuit (WAD1) for detecting and decoding a carrier frequency f A0 , address information and a block synchronization signal from the meandering groove geometry; a data-sequence generation circuit for generating a recording data sequence, a laser-power modulation circuit (WP1) for modulating a recording laser power in accordance with the recording data sequence, a reference signal generator (CK1) for generating a data reference clock T, and a data-sequence synchronization circuit for synchronizing a data sequence, which is to be written in the given recording block, with the start position of the recording block by comparing in phase between a reference signal f R0 , which is obtained by dividing the data reference clock at a particular radius by N (N is an integer), and the carrier frequency f A0 which is detected at the given address from the meandering groove geometry, and also making a fine adjustment of r.p.m. of the disc so as to satisfy a relation f d0 =N·f A0 .