Function class with a variable period

Abstract

The article points that there exist signals having varying period and shows some mathematical problems related with such signals studying. It should be noticed however, that neither theory for such signals is available nor methods are developed to investigate analytically functions with varying period as a class. Taking into account this situation, the article discusses such class and describes its important subclass, in which special attention is paid to superpositions of power and trigonometric functions. The above-mentioned elementary functions are supposed to be used for creating analogues of systems of orthogonal trigonometric functions.