| 摘要 |
PROBLEM TO BE SOLVED: To perform more reliable envelope detection. SOLUTION: When the absolute value of a read signal tends to increase with respect to each of envelope detection on a positive pole side and envelope detection on a negative side, a value complying with the difference between a sampling value and an accumulation envelope value is imparted with the absolute value of the accumulation envelope value so as to increase the absolute value, and thus the accumulation envelope value is updated. Conversely when the absolute value tends to decrease, the absolute value of the accumulation envelope value is decreased at a value proportional the envelope value without allowing the absolute value to follow the sampled value. As a result, the envelope detection more reflecting an actual waveform as compared to a conventional technology of rectifying and smoothing the read signal can be performed. Namely, the envelope detection more reliable than before can be performed. COPYRIGHT: (C)2009,JPO&INPIT
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