| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to measure the width of jitter by moving a strobe signal sequentially, detecting the presence or absence of fails and obtaining the rear-edge position and the front-edge position of the jitter. SOLUTION: From a test-pattern generator 20, a specified reference clock signal 21clk , is supplied into a reference-clock input terminal 11 of a DUT. A fail counter 40 initially sets the position of a strobe signal at the position of the rear-edge side of jitter, which does not detect a fail. Then, the timing position of the strobe signal is sequentially moved forward until the fail counter 40 detects the fail for a specified time. The position of the strobe signal when the fail is detected is made to be the jitter rear-edge position Max . Furthermore, the fail counter 40 initially sets the position of the strobe signal at the position of the front-edge side of the jitter for detecting all fails. The timing position of the strobe signal is sequentially moved to the rear side. The position when all fails are not detected is made to be the jitter front-edge position Min . The difference between the rear-edge position Max and the front-edge position Min is obtained and made to be the width of the jitter. |
