| 摘要 |
PROBLEM TO BE SOLVED: To shorten a period of time required for evaluating a reproduction signal by efficiently extracting a signal to be evalueted recorded in an optical disk. SOLUTION: An evaluation object pulse specifying circuit 54 inputs a reproduction signal through a binarization signal generating circuit 52 and a delay circuit 53, and outputs a detection pulse for each pulse width to be evaluated. A digital reproduction signal generating circuit 60 converts the reproduction signal to a digital reproduction signal by sampling with the prescribed sampling rate, delays it more than a binarization signal supplied to the evaluation object pulse specifying circuit 54 by the prescribed quantity, and supplies it to switch circuits 61 to 64. The switch circuits 61 to 64 supply the digital reproduction signal to amplitude calculating circuits 65 to 68 over the prescribed time in response to the detection pulse. The amplitude calculating circuits 64 to 68 store the supplied digital reproduction signal, calculates a feature value of the reproduction signal, and supply it to a controller 70 to evaluate the reproduction signal. COPYRIGHT: (C)2008,JPO&INPIT
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