Electronic data processing apparatus and method for sound synthesis using transfer functions of sound samples

Abstract

A method and an electronic data processing apparatus for wave synthesis that retains the true qualities of naturally occurring sounds, such as those of musical instruments, speech, or other sounds. Transfer functions representative of recorded sound samples are pre-calculated and stored for use in an interpolative process to generate a transfer function representative of the sound to be synthesized. The preferred transfer functions are Chebyshev polynomial-based transfer functions, which assure a highly predictable harmonic content of synthesized sound. Output sound generation is driven by time domain signals produced by reconversion of a sequence of interpolated transfer functions. Non-harmonic sounds are synthesized using multiple frequency inputs to the reconverting (waveshaping) stage, or by parallel waveshaping stages. Speech sibilants and noise envelopes of instruments are synthesized by the input of noise into the waveshaping stage by modulation of a sinusoid with band-limited noise.