| 摘要 |
<p>An offset correcting circuit for encoder which can detect accurate offset values even when the sampling period of a low-speed A/D converter, etc., is long, is hardly affected by noise, and is used for such an encoder that detects an angle signal based on digital signals obtained by the A/D-conversion of two signals having phases which are shifted from each other by about 90° at the same timing. The offset correcting circuit is provided with an offset detecting circuit which finds the offset value of one of the two signals by using the A/D-converted value of the signal when the A/D-converted value of the other signal is zero or its vicinity and a compensation circuit which compensates for the phase offset of one signal by using the offset value detected by means of the offset detecting circuit.</p> |
