Method and apparatus for detecting motion through a transparent enclosure, with spurious information detecting and compensating means

摘要

An electro-optical encoder is disclosed of the type used for reading utility meters. The encoder includes at least one light source for directing light onto the edge of the rotating disk of the utility meter. At least one sensor receives information reflected from the metered disk in pulse form upon sensing the calibration mark on the disk. A compensation circuit is connected to the sensor for detecting spurious information reflected from the disk and compensating for the spurious information to produce an accurate signal reflecting metered product usage for delivery to a final output. The compensation circuit includes a counter for being set to an integer corresponding to an empirically determined number of pulses sensed by the sensor during a single rotation of the meter disk. The counter counts down to one and then transmits downstream a single pulse representing one revolution of the meter disk and is then reset.