摘要 |
An integrated circuit is shown for use as a controller for a track sensor used with document processors. The track sensor includes a light source and a light detector. The circuit monitors the signal from the light sensing portion of the sensor, comparing the signal with a standard value and providing a feedback signal to the light source to adjust the intensity of the light to compensate for the effects of aging, holes in a document, the accumulation of dirt on sensor lenses and the like. The circuit determines when the leading edge of a document arrives and when the trailing edges pass by. It includes elements which prevent false indications that the trailing edge has passed when holes go by the sensor.
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