Through the use of an electronic differential analyzer arranged to give a sixth-order approximation of the Laplace shift operator, it is possible to reproduce an input signal and delay it T seconds when the highest angular frequency present in the input signal does not exceed 12/T. Inaccuracy due to nonlinear phase shift is less than 2% under these conditions. This device requires only linear computing elements, and will permit delays of seconds within a finite frequency spectrum. An application to a closed loop industrial control problem is cited and other applications are suggested.

Many people engaged in the development of precision analog computing equipment have concluded that the two most useful computing circuit elements are a stabilized d-c amplifier and a high-speed precision switch. The first requirement is met by a circuit disclosed by Goldberg.1A method of stabilizing a large number of d-c amplifiers with a single pulse amplifier was first reported by Ingerson.2