ROTATIONAL POSITION DETECTING EQUIPMENT

PURPOSE:To detect an absolute value of a rotation angle in a body of rotation stably and with a high resolution by generating a sine wave signal, a cosine wave signal, an inverse sine wave signal and an inverse cosine wave signal based on the rotating motion of a body of rotation and further by detecting an absolute rotational position based on a linear approximate signal and a division signal further generated. CONSTITUTION:Based on the rotating motion of a body of rotation, a sine wave signal S (SIN), an inverse sine wave signal S(-SIN) and a cosine wave signal S(COS) and an inverse cosine wave signal S (-COS) are generated. From these four signal waveforms, a linear approximate signal S20 is obtained. Moreover, by comparing the signal level of these four signals, the division signals SD1, SD2, SD3 and SD4 dividing the absolute rotation angle of the body of rotation for respective linear approximate regions are obtained. Here, based on the linear approximate signal S20 and divided signals SD1, SD2, SD3 and SD4, the absolute rotational position is detected by a rotational position detection circuit 32. By doing this, the absolute rotational position of the body of rotation can be detected stably and with a high resolution.