Discrete analogue-computer compensation of sampled-data control systems

The paper describes an analogue computer which can solve pulse transfer functions and operate as a discrete controller for compensation of sampled-data or continuous systems. Operational amplifiers and silicon-diode switches are combined to perform the basic functions of sampling, holding and time delay. The accuracy obtainable is comparable with that of digital controllers, but the analogue computer has the advantages of simplicity of setting-up and low cost. Adjustment of the controller parameters is easy, and the computer can be used to determine the coefficients of the pulse transfer function for optimum operation before a digital computer is employed. A simplified method of discrete-controller design for saturating sampled-data systems is also presented.