| 摘要 |
PURPOSE:To improve the detecting accuracy of drop-out by providing a window comparator and setting threshold levels at both sides of the window comparator centering on the zero point level. CONSTITUTION:The threshold voltage levels E and -E are impressed to the minus input terminal of a comparator 5 and the plus terminal of a comparator 6 on the basis of the zero point level Z. If a drop-out arises at a place near the reference level E', the inverse output signal of the comparator 6 keeps a high level for a prescribed period of time. Thus the drop-out is detected. In case a drop-out occurs at a place near the reference level -E, the inverse output signal of the comparator 5 keeps a high level for a prescribed period of time. Thus the drop-out is detected. In such a way, the detecting accuracy is improved for the drop-out. |
