| 摘要 |
PURPOSE:To improve detection accuracy, by logically processing electric signals obtained from magnetic resistance effect element patterns, and obtaining two phase electric pulse signals having the pulse number twice the number of teeth and the phase difference of 90 deg.. CONSTITUTION:The sine wave electric signals a, b, a', and b', which are outputted from the magnetic resistance effect element patterns by the variation in magnetic force caused by the rotation of a magnetic gear 7, are shaped by waveform shaping circuits 12-15, and become rectangular wave electric signals A, B, A', and B', which in turn become the electric pulse signal outputs P1 and P2 through exclusive OR circuit 16 and 17. The signals A and B have the phase difference of 90 deg.. When said signals A and B are logically processed in the exclusive OR circuit 16, the output phase signal P1 having the pulse width of 90 deg. is obtained. The signal A' and B' also have the phase difference of 90 deg., and the similar output pulse signal P2 is obtained through the exclusive OR circuit 17. Both pulses P1 and P2 become the electric pulse signal which have the number of pulses twice the number of the teeth of the gear and the phase difference of 90 deg.. In this way, the detecting accuracy can be improved. |
