| 摘要 |
PURPOSE:To efficiently test an operation limit of a prescaler in a short time by providing a pulse pattern generator for outputting the first and the second pulse train signals and a timing signal which has synchornized with the first pulse train signal. CONSTITUTION:A pulse pattern generator 1 outputs pulse train signals C1, C2 and a timing signal C3 which has synchronized with the signal C1. As for the signal C1 (2), it rises at the time of t1, t2..., and the signal C2 (3) consists of a pulse P1 of time width has joined together two inspection times TS, TH centering around the time t1 against the signal C1, and pulses P2, P3 which rise before the time TS and after TH against the time t2, respectively. In such a way, when the signals C1, C2 are applied to terminals CK, D of a prescaler 3, respectively, it is recognized that the terminal D is '1' at a rise edge of the signal C1, and it appears in an output terminal Q as shown in (4). Accordingly, as shown in (5), by the signal C3 which has synchronized with the signal C1, a pulse pattern detector 2 samples an output Q, and by discriminating its level [O mark of (4)], whether the prescaler 3 satisfies each time of set-up and holding as per specifications or not is discriminated. |
