| 摘要 |
PURPOSE:To make it possible to certainly and easily judge the result of the calibration of an attenuated probe, by performing the judgement of the relation between the output signal of the probe and set levels with respect to the max. value and the min. value thereof. CONSTITUTION:In a logic analyser 34, the output level T/H of DAC 42 is set to a max. value so as not to cross the output wave form Vi of a probe 72 under the control of CPU58 while the trigger signal TL from DAC44 is set so as to obtain a trigger signal TR at the point of time of the rising point of a rectangular wave signal from a calibration signal generator 68 supplied to the probe 72 as well as to cross the wave form Vi at a low level. Memory 50 stores the output of a comparator 36 at every a clock signal and, after the generation of the signal TR and the completion of the high level period of the rectangular wave signal, the relation of the wave form Vi and the T/H leve is stored. In this case, the crossing of the T/H level and the wave form Vi and, subsequently, the crossing of the T/H level and the wave form Vi in the total period of the high level of the rectangular wave signal are respectively judged and, when each judgement results are approved together, it is judged that the probe is calibrated. |
