RECORDING AND REPRODUCING METHOD OF BINARY INFORMATION

摘要

PURPOSE:To demodulate modulated data to binary data correctly even if a peak shift is generated in a reproduced signal by the secondary distortion of a reproducing system, by performing the second modulation and demodulation besides the first modulation and demodulation. CONSTITUTION:Binary data is inputted to an input terminal 19 and subjected to MFM modulation by the first modulating part 20. The modulated waveform due to MFM modulation outputted from the first modulating part 20 is subjected to the second modulation. The modulated waveform is inverted in every inversion position and the middle of two continuous inversion positions of the MFM modulated waveform by the second modulation. The second modulated data attained by the second modulating part 21 is recorded by a recording part 22. After this data is reproduced by a reproducing part 23, the second modulation is demodulated by the second demodulating part 24. The second demodulating part detects the leading edge of the second modulated waveform (b) to output a pulse (c). Since this pulse wave (c) is equal to pulses which detect the leading edge and the trailing edge of the first modulated waveform (a), this pulse wave (c) is subjected to MFM demodulation by the first demodulating part to output demodulated binary data from a terminal 26.