Time-integrating acousto-optic correlation in Gaussian noise

An acousto-optic time-integrating correlator with center frequency of 80 MHz, bandwidth of 40 MHz, a time aperture of 10 /spl mu/s and a signal bandwidth of 20 MHz was designed and assembled. The influence of additive Gaussian noise on the correlation peak was measured and analyzed for varying SNR levels. A novel electronic method for estimating the overall optical misalignment in the processor was devised and tested. It represents a simple and robust alternative to purely optical procedures. The resolution accuracy of the method is shown to be limited by the CCD pixel dimensions. As a side result, the scaling law that apply to the output signal when using CCD detection is also derived. The correlator is particularly useful for radar signal processing.