PERFORMANCE MODELS OF CORRELATORS WITH RANDOM AND SYSTEMATIC PHASE ERRORS

Hybrid correlators are composed of numerous nonideal electronic and op tical components that, to one degree or another, limit performance thr ough unintended transformations of signals. Many of these effects show up as phase errors at a spatial light modulator (SLM) plane. The erro rs can be described as random variables, or as systematic offsets from the correct phases, as appropriate. Sources of systematic phase error s include quantizing circuits, incorrect or nonlinear amplifier gain, limited range phase modulators and residual phase modulation of amplit ude-mostly SLMs. Random phase errors arise from electronic noise and f abrication variations of SLMs. Several systematic and random filter pl ane errors are related through a single parameter that describes the a mount of phase mismatch. A model of peak-to-noise ratio (PNR) is also presented that describes the combined effects of random and systematic errors. This expression contains the products of two functions, one t hat depends only on systematic, the other on random, phase mismatch. P NR is also a function of the number of pixels in the filter plane modu lator and a normalized moment of the amplitude of the image spectrum. The model is useful for developing phase error budgets for correlation systems.