METHOD FOR ANALYZING SIGNAL, AND METHOD FOR INSPECTING OPTICAL RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To efficiently judge and select a signal to be measured and to improve the automatic measurement accuracy by measuring the maximum value and the minimum value of an input signal waveform to set a signal level which is smaller than the maximum value and is larger than the minimum value, measuring a point on a time base where the signal level and the input signal waveform cross each other and selecting a signal where the time interval of the point exists within a preliminarily set range. SOLUTION: An optical recording medium recording and reproducing device 2 reproduces the data of an optical recording medium 1 and outputs a reproduced signal and an index signal. An index signal detection circuit 5 detects an index signal and outputs a trigger signal through a timer circuit after a prescribed delay time has passed. A computer 7 measures the maximum value (Vmax) and the minimum value (Vmin) of signal waveforms from an oscilloscope 4 on the basis of the trigger signal, sets a signal level (Vs) that becomes Vmax>Vs>Vmin, next measures a point on a time base where the level Vs and the signal waveform cross each other and selects a signal waveform whose time interval exists within a preliminarily set range.