| 摘要 |
PROBLEM TO BE SOLVED: To reproduce the super high density recording information independently in high S/N and at low error rate by discriminating the reproduced signal of a minute recording magnetic domain from the reproduced waveform in such a manner that a high-pass filter with the cut-off frequency higher than the optical resolution of a light spot is connected to a reproduced waveform detecting part. SOLUTION: The state of the magnetic domain is progressed to states 1, 2, and the change of the shape of magnetic domain is progressed in the state 3 at the response higher than the moving speed of a laser spot around the peak. However, the many peaks are fallen away at the detection DC slicing this reproduced signal. Then, the state 3 is underscored by the high-pass filter HPF since the change of the shape of magnetic domain at the state 3 is faster than the moving speed of the laser spot. At this time, the recording magnetic domain of 0.2μm is easily discriminated by DC slicing the waveform obtained as the f-characteristic ofλVL/NA<=fc<=Amp (λ: wavelength, VL: linear speed of medium, NA: NA of objective lens) with the cut-off frequency fc of the HPF, thereby the highly accurate reproduced signal is obtained.
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