XII. STATISTICAL COMMUNICATION THEORY

This group is interested in a variety of problems in statistical communication theory. Our current research is primarily concerned with: nonlinear systems with gaussian inputs, general nonlinear operators, characterization of random signals, optimum detec-tion of noisy frequency-modulated signals, pulse code modulation systems, a level selec-tor tube, removal of noise in phonograph records, and extension of the dynamic range in tape recording. 1. The study of nonlinear systems with gaussian inputs involves the generalization of Dr. Norbert Wiener's orthogonal expansion for a nonlinear system with a single input and a single output to an expansion for a nonlinear system with multiple gaussian inputs and a single output. Optimum filtering and prediction are two possible applications. The subclass of nonlinear systems that are composed of no-memory squaring devices and linear devices is receiving special attention because of the comparative simplicity in analysis. 2. A primary objective in the study of general nonlinear operators is a rigorous treatment of the nonlinear feedback problem. The mathematical technique of iteratio