| 摘要 |
A circuit provides a normalized position signal in response to a position of an illuminated spot on a lateral effect photosensor. The photosensor provides a concurrent pair of analog signals. The spot is illuminated by a light emitting diode. The circuit includes a summing circuit that provides a sum signal in response to an algebraic sum of the pair of signals, a first difference circuit that provides the position signal in response to the algebraic difference between the pair of signals, and a second difference circuit that provides an error signal in response to the algebraic difference between a reference signal and the sum signal. The error signal is coupled to the light emitting diode for governing an intensity of the spot, thereby normalizing the position signal.
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