| 摘要 |
An interpolation apparatus in an encoder includes an analog-to-digital converter for digitizing a sine wave signal and a cosine wave signal, respectively. An amplitude level detecting circuit detects each amplitude level of the digitized sine wave signal and cosine wave signal. A computing circuit multiplies the amplitude level of one of the signal by an interpolation position parameter according to a tangent value at an interpolation position. A comparing circuit compares an output from the computing circuit to an output from the amplitude level detecting circuit. The comparison is made at every the interpolation position. A region detecting circuit identifies a region sectionalized by the interpolation positions adjacent to each other based on an output from the comparing circuit corresponding to each the interpolation position. The phase angle of the sine wave signal and the cosine wave signal exists in the region.
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