A two-dimensional acousto-optic signal processor is shown to be useful for providing simultaneous spectrum analysis and direction finding of radar signals over an instantaneous field of view of 360 deg. A system analysis with emphasis on the direction-finding aspect of this new architecture is presented. The peak location of the optical pattern provides a direct measure of bearing, independent of signal frequency. In addition, the sidelobe levels of the pattern can be effectively reduced using amplitude weighting. Performance parameters, such as mainlobe beamwidth, peak-sidelobe level, and pointing error, are analyzed as a function of the Gaussian laser illumination profile and the number of channels. Finally, a comparison with a linear antenna array architecture is also discussed.