| 摘要 |
PURPOSE:To obtain a frequency generator, which can generate a highly accurate rotation monitor signal even when it is miniaturized, by arranging a plurality of layers of detection pattern oppositely to a multipolar rotary magnet. CONSTITUTION:A rotary magnet 1 is arranged with 2n magnets and a plurality of layers of detection pattern have double structure, wherein the upper layer is arranged with a detection pattern 4 and the lower layer is arranged with a detection pattern 6. These patterns 4, 6 comprise rectangular pattern folded with same pitch as the magnet and since the latter is shifted by 1/3 pitch to the right from the former, the signal generated from the detection pattern 6 has such waveform E2 as shifted by 1/3 pitch from the signal waveform El generated from the detection pattern 4. In other words, signals generated from the patterns 4 and 6 are shifted by 1/6 period from each other. Since two types of signals E1, E2 have phase shift, finer angle can be detected as compared with the case employing only one signal. |
