| 摘要 |
PROBLEM TO BE SOLVED: To automatically measure the numerical aperture of an eye pattern by obtaining a maximum value and a minimum value from whole waveform data amplitude level values, obtaining whole times when the amplitude level value becomes the same as a desired comparison level value within the range from the maximum value to the min. value, obtaining the minimum value and the maximum value from the whole times and obtaining an eye numerical aperture. SOLUTION: The maximum value and the minimum value are obtained from the whole waveform data amplitude level values stored in a storage device 30. The desired comparison level value within the range from the maximum one to the min. one is made to be Y1 and a comparison level Y1 is obtained by Y1=(a+b)/2 as the average value of the maximum value (a) and the minimum value (b). The whole waveform data amplitude level values stored in the storage device 30 are retrieved and whole time data are obtained, when the amplitude level value becomes the same as the comparison level value Y1. The min. value T1 and the minimum value T4 are obtained from the whole time data, a comparison time T is obtained within the range and, then, the eye numerical aperture is obtained.
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