FFT multi-frequency synthesizer

An fast-Fourier-transform (FFT)-based procedure which synthesizes the waveform directly from the set of spectral components is presented. A Gaussian window function is introduced to deal with noninteger frequencies. There exists an optimal condition for the width of the window which minimizes the numerical error. Techniques for the generation of linear envelope, decay, and frequency modulation are presented. Numerical results verify the validity of this procedure.<
>