| 摘要 |
PURPOSE:To eliminate the effect of erroneous pulses owing to the vibration etc. of a rotator by the exclusive OR of two phases of mutually shifted phases and the pulses at the rise and fall of one of the pulses in the forward and backward revolution detector for rotators. CONSTITUTION:Two phases of phases A, B of shifted phases are generated by the two detecting elements which are placed near the rotator and turn on and off according to revolutions. In a logic circuit 21, the exclusive OR pulse (a) of the pulses A, B is obtained. In a delay circuit 23, and a logic circuit 22, a pulse (b) is obtained at the rise and fall of the pulse B. The pulse (b) is generated at the high level of the pulse (a) while the rotator is revolving forward and at the low level while it is revolving backward and therefore, the pulses (b) are added or subtracted with an addition-subtraction counter 24 according to the high and low levels (that is, the revolving direction) of the pulses (a), whereby the number of revolutions is counted. Even if the erroneous pulses of a short width are produced in the pulses A in the forward and backward revolutions of the microangle owing to the vibrations of the rotator, no effect is given to the counting of the pulses (b). |
