| 摘要 |
PROBLEM TO BE SOLVED: To provide a comparator in which influence of noise input is reduced by setting a hysteresis width to be wide when a signal is not present, and sensitivity is improved by setting the hysteresis width to be wide when a signal is inputted. SOLUTION: This comparator is equipped with a differential amplifier for amplifying a differential voltage ΔV(=VA-VB) as far as a level where a logic level can be judged, a comparing means 2 provided with a hysteresis circuit which can set two hysteresis widths (ΔVa, ΔVb) shown by figures (b) and (c) with respect to the differential voltage ΔV(=VA-VB), and a logic pattern detecting means 3 constituted of a counter, a storage device, a referring circuit, etc. When a detection pattern which is set previously in the storage device is detected from a fixed logic pattern of the head of a pulse train of output voltage VO supplied from the comparing means 2, the logic pattern detecting means 3 supplies a switching signal VS and performs controlling so as to switch over the hysteresis width of the hysteresis circuit of the comparing means 2. |
