SECTOR MARK DETECTING CIRCUIT

• Main Authors: MATSUDA FUMIO, IWATANI YASUYUKI, OZAKI MINORU
• Format: Patent
• Language: English
• Published: 19.04.1989
• Subjects: INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHYSICS

PURPOSE:To prevent the erroneous detection of a sector mark by providing a first threshold logic circuit which detects the coincidence of a first prescribed or more number and a second threshold logic circuit which detects the coincidence of a second prescribed or more number different from the first prescribed number from the output of the first threshold logic circuit. CONSTITUTION:The first threshold logic circuit 135 which divides parallelized reproducing signals into required number of bits, and compares the divided required number of bits with a reference pattern at every block and detects the coincidence of the first prescribed or more number, and the second threshold logic circuit 155 which detects the coincidence of the second prescribed or more number different from the first prescribed number from the output of the first threshold logic circuit 135 are provided. In other words, a factor impossible to detect a defect or a noise, etc., can be removed by providing the first threshold logic circuit 135, and the number of coincidence of each block can be detected by providing the second threshold logic circuit 155. Therefore, it is possible to take a large difference between the number of coincidence blocks generated at a regular position and that of coincidence blocks generated at a position that is not the regular position, and a large second threshold can be set. In such a way, it is possible to prevent the erroneous detection from being performed.