Speech generation using variable frequency oscillators
AssigneeFirst Byte
InventorsRichard P. Sprague, William J. Arthur
Life of this patent
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Abstract
Artificial speech is produced with minimized memory requirements by using a bank of digital oscillators to produce voiced sounds by combining multiple harmonies of a fundamental-frequency sine wave, and using only one of these oscillators to reproduce stored nonsinusoidal waveforms for unvoiced sounds. Sufficient dynamic range is achieved with a minimum number of oscillators by generating only every other harmonic at the higher frequencies. All harmonics are derived from a single stored digitized sine wave by using stored sets of skip counts and amplitude codes corresponding to various voiced sounds to be produced.
Claims6
A speech generation system, comprising:
- a) means for producing indicia identifying voiced and unvoiced speech elements to be produced;
- b) a plurality of digital oscillators;
- c) means for combining the outputs of said oscillators to produce speech information;
- d) means connected to said combined oscillator outputs for converting said speech information into audible speech sounds;
- e) a waveform memory for storing, for each of said voiced speech elements, a common sinusoidal waveform and for storing individual speech element waveforms for unvoiced speech elements;
- f) a parameter memory for storing sets of oscillator operating parameters associated with individual voiced speech elements;
- g) said waveform memory and parameter memory being connected to said oscillators;
- and
- h) means for operating said oscillators so as to produce outputs representative of a selected one of said waveforms, as modified by selected ones of said parameters, the selection being responsive to said speech element identifying indicia.
A method of producing artificial speech sounds, comprising the steps of:
- a) simultaneously producing from a common stored sinusoidal waveform associated with a specific voiced speech sound a plurality of sine waves, each being a harmonic of the lowest-frequency since wave being produced, and combining said sine waves to form said voiced speech sound;
- b) producing single speech sound waveforms to form unvoiced speech sounds;
- and
- c) concatenating said voiced and unvoiced speech sounds to form speech.
Dependencies are inferred from the claim text.