A simplified coherent optical correlator.
The basic theory plus a few nonreal time experimental results of a coherent optical analog correlator consisting of only a ngle transforming lens are given. The two spatial signals to be correlated were written on two side-by-side photographic transparencies (an ultrasonic light modulator may be employed for real time operation). Two types of spatial carriers were used to separate the desired correlation signal from spurious signals in the output diffraction plane. Frequency shift of one input signal may be determined by measuring the spatial shift of the output diffraction pattern.
Felstead
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