| 摘要 |
PURPOSE:To obtain a suppressing effect whose peak shift is sufficient, in case of having such a recording density as a ratio of a half-amplitude level of an isolated reproducing signal and a bit period of a data exceeds ''2'', by emphasizing an output by a constant rate as a frequency increases, to the tertiary higher harmonic frequency of the frequency of 1/2 of the highest recording frequency, at the time of reproducing, and providing an equalizing means consisting of a low- pass filter which has the cut-off frequency of two times of the highest recording frequency and also a constant roll-off rate in the vicinity of the cut-off frequency. CONSTITUTION:A reproducing signal inputted to a reproducing signal input terminal 7 is inputted to a differentiating circuit 8, and emphasized by a 6dB octave to the tertiary higher harmonic component of 1f. A low-pass filter 9 is not attenuated until a frequency of the tertiary higher harmonic of 1f, selected so that a cut-off frequency becomes about two times of 2f, and the roll-off rate is 0.2. An output of the low-pass filter 9 is further inputted to a phase correcting circuit 10, and the phase is varied by the differentiating circuit 8 and the low- pass filter 9, therefore, it is corrected. |
