Computationally efficient sine wave synthesis for acoustic waveform processing

A method for suppressing tonal noise artifacts during the reconstruction of an acoustic waveform from a sinusoidal parametric representation of the waveform, the method comprising;

• estimating a noise envelope from a set of variable frequency components having individual amplitudes which comprise a parametric representation of the waveform;
• reconstructing an acoustic waveform from said parametric representation;
• and
• filtering said reconstructed waveform using said noise envelope estimates to suppress tonal noise estimates.

A method of deriving phase values for frequency components during reconstruction of an acoustic waveform from a sinusoidal representation of the waveform, the method comprising:

• determining a phase of the fundamental frequency by integration of a pitch frequency obtained by linear interpolation of matched fundamental frequencies between successive frames;
• determining a pitch onset time by locating the time at which the phase function crosses the nearest multiple of the phase synchrony point;
• and
• allocating phase values to the frequency components, such that all of the frequency components come into phase every pitch onset time.

A system for processing an acoustic waveform, the system comprising

• sampling means for sampling a waveform to obtain a series of discrete samples and constructing therefrom a series of frames, each frame spanning a plurality of samples,
• analyzing means for analyzing each frame of samples to extract a set of variable frequency components having individual amplitudes,
• tracking means for tracking said components from one frame to a next frame, said tracking means including matching means for matching a component from the one frame with a component in the next frame having a similar value regardless of shifts in frequency and special energy,
• interpolating means for interpolating the values of the components from the one frame to the next frame, including means for performing an overlap-and-add function utilizing Fourier analysis to generate a reconstruction of said waveform.

A receiver for receiving a coded parametric representation of an acoustic waveform in which the representation comprises as set of variable frequency components having individual amplitudes defining sine waves which can be summed to recreate the waveform at a particular frame of time, the receiver comprising:

• decoding means for extracting a set of frequency components having individual amplitudes from each frame of a coded representation of an acoustic waveform;
• tracking means for tracking said components from one frame to a next frame, said tracking means, including matching means for matching a component from the one frame with a component in the next frame having a similar value regardless of shifts in frequency and spectral energy;
• and
• interpolation means for interpolating the values of the components from the one frame to the next frame, including means for performing an overlap-and-add function utilizing Fourier analysis, to generate a reconstruction of said waveform.