| 摘要 |
An apparatus for accurately detecting and digitally displaying the centrum of the location where a luminous energy beam impinges a shift register scanned linear photodetector array. With the commencement of the array scan, clock pulses corresponding to successive photodiodes are accumulated in a counter, continuing until an illuminate photodiode, with a video response above the detection threshold, is encountered. Thereafter, clock pulses are locked out while only alternate video pulses reach the counter. The onset of the succeeding scan locks out the video pulses, leaving the counter display at the previously accumulated count for an extended period defined by a supplemental sample timing circuit. The sampling of scans provides a display sufficiently stable for visual monitoring.
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