A general optical system for processing temporal signal waveforms is described. In this system, a frequency-variant spectrum analyzer system is used in conjunction with an interferometric optical hetero-dyne processor. The capability of the frequency-variant analyzer to control the position and resolution of signal components allows for the general mixing of a signal and a local oscillator. This mixing results in a frequency dependent redistribution of the signal components useful for bandwidth compression and expansion or for more general spread-spectrum signaling.

Frequency-Variant Signal Waveform Processing Using 2-D Optical Processors

Coherent optical systems have been employed in many configurations for the spectral analysis of signal waveforms. With some systems, signal time-bandwidth products approach 107, and real time or near real time analysis is now common. We describe here methods for obtaining frequency-variant time and frequency resolution with a coherent optical spectrum analyzer and for displaying signal spectral content vs. arbitrary functions of frequency. These methods greatly enhance the applicability of optical systems to specific spectral analysis problems, A constant proportional bandwidth-log frequency system is considered as an example. Applications to frequency-mapping signal processing are also discussed.

J. Florence

Papers

Frequency-variant optical systems for signal analysis and processing