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Hardware implementation of the steepest descent algorithm, as applied to multichannel adaptive jamming cancellation, requires the realtime correlation of wide bandwidth signals from multiple input channels. The described optical system uses a single-channel acousto-optic (AO) deflector as an input device for the adapted main antenna signal, where multiple jamming sources mask the target return, and a multichannel AO deflector as the input device for an array of auxiliary antennas, each receiving jamming energy. A time-integrating correlation between the main and auxiliary channels is calculated optically and produces an update to each weight function (stored in computer memory) in accordance with a steepest descent algorithm. The updated weight functions are optically reconstructed and used to tap a multichannel AO delay line, which carries the information from the array of auxiliary channels. A spatial sum of the output from the weighted delay line yields an estimate to the noise in the main channel. The multichannel optical time-integrating correlator has demonstrated realtime parallel computation of the correlation between two wide bandwidth auxiliary channels and the adapted main channel.

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Acousto-optic spectrum analyzers provide a convenient means of separating wide-bandwidth signals into their frequency components. By a change in the rf input signal into the spectrum analyzer and by the provision of additional digital postprocessing, it is possible to perform radiometry, signal autocorrelation, and matched-filter reception. Although the acousto-optic device has a space-integrating architecture, the matched-filter receiver can be implemented for signals having time durations much longer than the acousto-optic cell. The resulting signal-to-noise ratio improvements from the receiver are consistent with the time-bandwidth product of the waveform, rather than the time-bandwidth product of the acousto-optic device. A mathematical foundation of the processor is presented along with specific receiver implementations. Computer-simulation and experimental results demonstrate key findings. In one experimental example, a linear-frequency-modulated waveform is matched-filter processed to recover a signal that is -24 dB with respect to the input noise floor.