An Acousto-Optic Receiver and Fast Spectrum Analyzer for Electromagnetic Signals in the VHF-UHF Range

The principle of a lightweight acousto-optic receiver and fast spectrum analyzer, capable of reception and analysis of electromagnetic signals in the VHF-UHF range, is described. The principle consists of first converting electromagnetic signals to ultrasonic signals that propagate in a solid transparent medium and subsequently separating these signals into many channels by light diffraction techniques. A multitude of diffracted light beams are formed, each of which contains an up-converted segment of the RF input signal band. Simultaneous signal detection in all channels is accomplished with an array of photodiode detectors. A detailed analysis of this signal reception technique is presented, along with a description of a laboratory model of the receiver-analyzer. Experimental data obtained on the performance of both this model and its component parts is described. Good agreement is found between theory and experiment. The experimental model operates over a frequency range from 200 to 500 MHz, with a 5.3-MHz continuous wave frequency resolution.