| 摘要 |
<p>An encoder device providing an enhanced sensing resolution includes an emitter that emits a beam of electromagnetic energy which is received by a number of detectors, such as four. Each detector outputs a signal indicative of when the detector receives the beam. A moveable member, such as a code disk or strip, is positioned to receive the beam from the emitter, where the moveable member alternately allows and prevents the beam to be received by the detector, for example, by allowing the beam to pass through spaced apart slots in the moveable member. The detectors are placed such that they produce detection signals which are 45 degrees out of phase with one another. In a different embodiment, a reticle is positioned between the moving member and detectors having multiple slots. The out-of-phase detection signals are used to sense the motion of the moveable member. The rising and falling edges of a first pair of the detection signals can be counted while rising and falling edges of a second pair of the detection signals is counted. The count information from the pairs can be added to provide a count having twice the sensing resolution as each of the pair counts.</p> |
