| 摘要 |
PURPOSE:To achieve a testing capacity per unit time and a higher measuring accuracy, by applying so-called sandwitching method of sandwitching a changing point of a timing edge at two time points while algorithm is incorporated allowing a jitter of a test cycle to enable reduction in time required for measure ment of a position of the timing edge. CONSTITUTION:When a voltage at a sampling time (t) is smaller than Vref, a measured value is set at 0, while, when it is larger than the value, the mea sured value is set at 1. Position at 0 and position at 1 are measured by a sam pling means and a result judging means so that two time points t1 and t2 sandwitching a changing point (x) of a timing edge 11 are determined to com pute a time point t3 as intermediate position. Here, when measured values are different at the time points t2 and t3, the changing point (x) exists between both the time points. So, the subsequent two time points t3 and t2 sandwitching the changing point (x) of the timing edge 11 are determined to compute a time point t4 as intermediate position therebetween. The above-mentioned operation is repeated to reach measuring resolutions. Algorithm is incorporated into a sandwitching method allowing a jitter of a test cycle thereby achieving a higher measuring accuracy.
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