| 摘要 |
PURPOSE:To accurately grasp a detection point which makes a reference point at the timing of commutation by providing masking period setting means for variably setting a masking period for keeping a detection signal undetected in response to the number of revolution. CONSTITUTION:The comparison of all operational amplifiers (Op) is not brought into existence at the time of low rotation but the Op becomes H to allow all monostable multivibrators (Mo) to be brought into operation. H is simultaneously outputted for a plurality of periods from a terminal Q. An L detection signal of a detection signal line is masked in an OR logic circuit 11 by the H output of the terminal Q for the longest period, so that a H signal showing the state of being undetected is outputted from the last output line. On the other hand, at the time of high rotation, comparison is brought into existence sequentially from the upper Op to output an L output from the Op. Consequently, the operation of the Mo is inhibited. As a result, when the number of revolution is increased, the Op outputs an L signal sequentially from the upper one to the lower one, and the operation of the Mo is sequentially stopped from the Mo for setting a long masking period of time to the Mo for setting a short masking period of. |
