| 摘要 |
PURPOSE:To limit the number of comparators by A/D-converting a wide part and the narrow part of a level interval by the same form, by using a reference signal to which level interval is unequal, and setting an input/output relation to a prescribed non-linear relation. CONSTITUTION:An analog input A is inputted to one terminal of plural comparators 13. Also, to the other terminal of the comparators 13, connecting points 1, 2-(n) of a ladder resistance 12 consisting of plural resistances connected in series to a constant-current source 11 are connected. A resistance value between each connecting point 1-(n) becomes the multiple of integer such as, for instance, 4R in both the end parts, and R in the center part, and the center part which requires high resolution, and both end parts which cause no trouble, even if the resolution is low are discriminated. In this state, a signal digitized by each comparator 13 is processed by a code comparator 14, and outputted through a ROM 15. In such a way, the ladder resistance is manufactured easily, the number of comparators is curtailed, and the cost of manufacture is reduced.
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