| 摘要 |
PURPOSE:To set automatically a delay time of a delay circuit to a delay time in a measured system by delaying an output signal of the delay circuit as a measuring signal by almost a delay time in the measured system. CONSTITUTION:A measuring signal SPN0 from a pattern generator 1 is fed to DFF 111-11m, its output signal is fed to a DFF 13 via an MPX 12 and a comparison signal SPN2 is outputted. A clock CLK' having a frequency being 16 times the bit frequency is fed to a ring counter 14 and 16 kinds of clocks are fed to an MPX 15 while being sequentially deviated by a bit changeover timing of the signal SPN0 at an interval of 1/16 of the bit period. A measuring signal SPN1 from a measured system 2 is fed to a starting detection circuit 16, a detection signal PD1 when the signal SPN1 changes to logical 1 and a detection signal PD2 when an output of a FF 13 is fed to a starting detection circuit 18 and changes to logical 1 are compared by a comparator circuit 17, and the difference is fed to a counter 19. Thus, the signals SSP0 and SPN1 are coincident. |
