A Classroom Demonstration of Correlation, Convolution and the Superposition Integral

A classroom demonstration has been developed which allows the correlation functions of a wide variety of pre-selected signals to be displayed on an oscilloscope. The demonstration utilizes standard equipment found in most undergraduate electrical engineering laboratories and requires no special construction of new equipment or extensive modification of existing instruments. All the steps involved in generating a given correlation function can be displayed in a logical step-by-step sequence from the input signals to the output function. Either autocorrelation or cross-correlation can be performed and the effects of varying different parameters illustrated. Additionally the same two signals can be convolved so that the validity of the superposition integral can be demonstrated. The application of correlation techniques to the detection of signals in the presence of noise can also be demonstrated. Examples of all these possibilities are given.