Abstract: An apparatus and method for generating a representation of an arbitrary signal wherein the signal is represented as a sum of reference signals derived from a standard wavelet defined on a grid in the frequency-time plane. The apparatus comprises a plurality of octave circuits, each octave circuit, in turn, comprising a plurality of band circuits that divide a frequency range covering the spectrum of the signal into equal intervals of logarithm of frequency. Each band circuit comprises a bandpass filter to select a frequency component of the signal and a correlator to correlate the signal component with a reference signal derived from a standard wavelet to produce a series of correlation values representing the signal for recordation in response to clock pulses received by the octave circuits.