Analogue recursive computer

A control computer is described which uses a serial digital program to control an arithmetic unit and storage system working entirely in the analogue mode. Storage is capacitive, using field-effect-transistor switches for data selection. Using conventional techniques, speeds of 20¿s per arithmetic operation are readily obtainable. The first application of this computer is to aircraft-gas-turbine control. A control program, for example, of a Rolls Royce Olympus 593B engine occupies 120 instructions, and the computation has a recursion time of 3ms. An accuracy of within 0.1% is obtainable.