Reproduction method and apparatus

An apparatus which reproduces information from an information recording medium, the information recording medium including:

• a reference wobble block which has a first wobble pattern representing a first information content;
• and
• an information wobble block which follows the reference wobble block and which has at least one of the first wobble pattern and a second wobble pattern representing a second information and different from the first wobble pattern,
• said apparatus comprising:
• a head which reads the reference wobble block and the information wobble block;
• and
• an information detection circuit which outputs information recorded in the information wobble block,
• said information detection circuit comprising:
• a heterodyne detector which heterodyne-detects a wobble pattern of the information wobble block and the first wobble pattern of the reference wobble block read by the head;
• and
• a binarizing circuit that performs:
• judging that information recorded in the information wobble block is identical with the first information, in the case the wobble pattern read from the information wobble block coincides with the first wobble pattern;
• judging that information recorded in the information wobble block is the second information in the case the wobble pattern read from the information wobble block is different from the first wobble pattern;
• and
• outputting one of the first information and the second information.