Patent ID: 7349303

Claim:
An information recording apparatus for recording a sequence of sync frames, indicative of data, onto tracks of an optical recording medium in which prepits are formed on lands between the tracks at given intervals, and in which sync patterns, providing synchronization on a sync-frame basis, are inserted in the sync frames such that each sync pattern has a length in a track direction larger than a length of one of the prepits and a position of each sync pattern matches with a position of at least one of the prepits, the information recording apparatus comprising: first sync information generating means for generating first codes that represent first sync patterns for a portion of the sync frames such that each first sync pattern is formed as a space on the recording medium; second sync information generating means for generating second codes that represent second sync patterns for the remainder of the sync frames such that each second sync pattern is formed as a mark on the recording medium so as to meet a low-frequency reduction scheme; sync information selecting means for selecting one of the first codes generated by the first sync information generating means and the second codes generated by the second sync information generating means; prepit position signal detecting means for detecting a prepit position signal from one of the prepits for each of the sync frames during the writing of the recording pulses to the recording medium; write position signal generating means for generating a write-position start signal based on the prepit position signal detected by the prepit position signal detecting means; and data encoding means for generating modulation codes based on the sync frames in which the codes selected by the sync information selecting means are inserted, by modulating the sync frames containing the selected codes in accordance with a predetermined modulation scheme, the data encoding means generating a sequence of recording pulses by converting the modulation codes through a predetermined conversion scheme, and the data encoding means starting outputting the sequence of recording pulses in accordance with the write-position start signal supplied by the write position signal generating means.