| 摘要 |
Two piezoelectric sensors (78, 80) are mounted on the back of a spring-plate (14) of a mechanical resonance scanner (10) on respective sides of a center line coinciding with an axis of rotation (16). As the scanner mirror (12) rotates back and forth the two sensors are accelerated and decelerated at a 180 DEG phase difference. Each sensor's output voltage crosses a zero level when the acceleration is unchanging. A differential amplifier (88) detects the zero-crossings for motion along the axis of rotation. Common mode rejection eliminates the non-rotational accelerations associated with external vibrations and shocks, and prevents masking the mirror's zero-crossings.
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