An object-oriented signal processing environment: The knowledge-based signal processing package

A LISP-based signal processing package for integrated numeric and symbolic manipulation of discrete-time signals is described. The package is based on the concept of signal abstraction in which a signal is defined by its non-zero domain and by a method for computing its samples. Most common signal processing operations are defined in the package and the package provides simple methods for the definition of new operators. The package provides facilities for the manipulation of infinite duration signals and periodic signals, for the efficient computation of signals over intervals, and for the catching of signal values. The package is currently being expanded to provide for manipulation of continuous-time signals and symbolic signal transformations, such as the Fourier transform, to form the basis of knowledge-based signal processing systems.