DIGITAL MODULATION METHOD, DEMODULATION METHOD, AND DIGITAL MODULATION DEVICE AND DEMODULATION DEVICE

PROBLEM TO BE SOLVED: To limit the error propagation to be short at the time of demodulation while reducing losses of memory capacity and to reproduce data at a low error rate, by arranging a state reset bit to reset an internal state of a modulation/ demodulation circuit under operation to a specified state during record- formatting. SOLUTION: A state reset bit(SRB) addition block 30 is provided in a data recording system which records information in record medium 5, being connected with a record modulation block 2 and a format encoded block 3, and SRB is added into channel bit string at a specified position in the record format of the data, and the channel bit pattern is composed so that the length of SRB becomes short enough compared with a synchronized byte. Thus, by reducing the loss of the memory capacity and limiting the error propagation to be short at the time of demodulation, a digital modulation and demodulation method and a device which enable the data to be reproduced at a low error rate are provided.