Sound synthesis process
AssigneeFrance Telecom
InventorsPhilippe Depalle, Xavier Rodet
Life of this patent
Estimating the term…
Abstract
A sound synthesis process. The invention relates to an additive sound synthesis process, as shown in FIGS. 1A and 1B, in which sample blocks (16) are determined by performing the inverse Fourier transform of successive frequency spectra. The time-superimposed sample blocks (16) are added in order to form a sequence of samples representing the reconstituted sound wave.
Claims20
Process for the synthesis of sounds, the steps comprising:
- A) generating a synthesis signal by superimposing time-displaced signal blocks, which are overlapped in time, each block being obtained by an inverse orthogonal transform of a constructed frequency spectrum,
- B) constructing said spectrum by carrying out the following steps:
- choosing a spectral envelope,
- then interactively and for each desired sinusoidal, discrete spectral frequency component, defined by its frequency, amplitude and phase parameters:
- multiplying the spectral envelope by the amplitude of the component weighted by its phase factor, which is computed such that the phases of a given said sinusoidal component in overlapping blocks are equal at a point where the amplitudes of the envelopes of this sinusoidal component in the two overlapping blocks are equal, so as to obtain a pattern representing said frequency component,
- adding the so obtained pattern to the spectrum being constructed,
- C) adding the spectrum corresponding to the unwanted part of the signal to be synthesized to the spectrum obtained in Step B.
A process for the synthesis of sounds from a sound signal corresponding to a sample block (Cj) digitally stored as discrete components including frequencies (fi), amplitudes (Ai), phases (.rho.i) and noise components (Bi), i being the number of discrete components, the steps comprising:
- selecting a type of frequency domain spectral envelope based on shape, said spectral envelope being of the window-type;
- sampling said spectral envelope at said frequencies (fi) to create a sampled spectral envelope;
- multiplying said sampled spectral envelope at each of the frequency points (fi) with a corresponding said amplitude (Ai) and phase (.rho.i) over a range of frequencies (fi) to obtain a pattern;
- adding said pattern with the spectrum being constructed to obtain an auto-correlated spectrum;
- adding said noise components (Bi) with said auto-correlated spectrum to obtain a frequency domain block;
- obtaining an inverse Fourier transform of the frequency domain block to obtain a time-displaced signal block;
- repeating said process for the synthesis of sounds for other sample blocks and obtaining a plurality of time displaced signal blocks, which overlap in time;
- and
- superimposing said time displaced signal blocks in real time to synthesize sounds.
Dependencies are inferred from the claim text.