Photo-electric direction finder

Abstract

Abstract 1534093 Photoelectric direction-finder THOMSON-CSF 19 Oct 1976 [21 Oct 1975] 43380/76 Heading H4D A photoelectric direction-finder comprises an optical device 1 for focusing the light radiation received from an observed field centred on the optical axis Z onto a plane detector device formed by a linear array of parallel detector elements 2; an arrangement 3 for modulating the radiation by the displacement of slots 5; reception channels (e.g. 6, 11, 7, 8) leading respectively from the detector elements, each channel comprising amplifying and filtering circuits 6, 7 and a threshold comparator 8; and a generator circuit 17 (Figs. 6-7, not shown) receiving an external control signal S2 to identify a first instant t 0 which precedes by a predetermined interval T 0 the time t 3 at which a target is expected to appear in the field, circuit 17 providing a common threshold U from the comparators 8 and producing an automatic adjustment thereof to an operation value U F higher than the inputs to the comparators during the interval T 0 . The automatic threshold adjustment thus serves to eliminate the effects of noise inputs to the detector. In an initial period T 1 , the threshold is set to a maximum U M , then reduced to a minimum U m at t 1 , then incremented in steps during a period T 2 until the operation value U F is reached. The detector also incorporates gates 11 and circuitry 10, Figs. 4-5 (not shown) to provide an electronic "window" for the observation field.

Inventors

No inventors recorded.

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