| 摘要 |
An optical sensor that uses laser radar techniques to determine the value of a mesaurand. The sensor comprises an encoder, an optical source, sensing means and detection means. The encoder has a plurality of tracks, each track including means for receiving an optical signal and for delaying the optical signal by an encoder delay that is a function of the measurand value. The optical source produces a chirped optical interrogation signal that is received by the sensing means and divided into N channel signals, such that each channel signal strikes one of the tracks. The sensing means delays each channel signal by a unique channel delay. The detection means receives the channel signals after they have struck the tracks, and mixes the channel signals with a facsimile of the interrogation signal, to produce a demodulated signal. The detection means analyzes the frequency components of the demodulated signal, to determine the encoder delays and thereby the value of the measured. The encoder preferably comprises a transparent moveable substrate having a variable pattern of reflecting elements on one side, and a uniform reflective coating on the opposite side.
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