RADIOMETERS, AUTOCORRELATORS, AND MATCHED-FILTER RECEIVERS BY MEANS OF ACOUSTOOPTIC SPECTRUM ANALYSIS

Acousto-optic spectrum analyzers provide a convenient means of separat ing wide-bandwidth signals into their frequency components. By a chang e in the rf input signal into the spectrum analyzer and by the provisi on of additional digital postprocessing, it is possible to perform rad iometry, signal autocorrelation, and matched-filter reception. Althoug h the acousto-optic device has a space-integrating architecture, the m atched-filter receiver can be implemented for signals having time dura tions much longer than the acousto-optic cell. The resulting signal-to -noise ratio improvements from the receiver are consistent with the ti me-bandwidth product of the waveform, lather than the time-bandwidth p roduct of the acousto-optic device. A mathematical foundation of the p rocessor is presented along with specific receiver implementations. Co mputer-simulation and experimental results demonstrate key findings. I n one experimental example, a linear-frequency-modulated waveform is m atched-filter processed to recover a signal that is -24 dB with respec t to the input noise floor. (C) 1997 Optical Society of America.