Three-Frequency Nonlinear Heterodyne Detection 2: Digital Communications and Pulsed Radar

Abstract

Part 1 of this paper [Appl. Opt. 14, 666 (1975)] dealt with the cw radar and analog communications uses of three-frequency nonlinear heterodyne detection. In this paper, we evaluate the technique for a number of specific pulsed radar and digital communications applications. Both the vacuum channel and the lognormal turbulent atmospheric channel are considered. It is found that the advantages of the technique in the pulsed/digital system are similar to those obtained in the cw/analog system. Computer generated error probability curves as a function of the input signal-to-noise ratio are presented for a variety of binary receiver parameters and configurations and for various levels of atmospheric turbulence. Orthogonal and nonorthogonal signaling schemes, as well as dependent and independent fading, are considered. When Doppler information is poor, performance is generally superior to that of the conventional heterodyne system.