| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem: some of old type LSI testers have no frequency measurement function of a signal output from DUT, when the period of the DUT or frequency characteristics is measured using such an LSI tester, a measuring device including an external frequency measuring instrument is purchased separately and the measurement needs to be performed by combination of the measuring instrument with the LSI tester, but new additional circuit for a test and/or a frequency measuring instrument needs to be added, thereby costs are increased and a program for controlling an external circuit needs to be created. SOLUTION: A frequency is measured using a function included in the old type LSI for determining agreement/disagreement of output of DUT and an expected value. When a signal from the DUT changes from L to H, counting is started. The number of counts is investigated during the time until the signal changes to L from H, and then the number of counts is investigated during the time until the signal changes to H from L. The both numbers of counts are added. The frequency is calculated based on the added numbers of counts and a period of a basic clock. COPYRIGHT: (C)2011,JPO&INPIT
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