Method and apparatus for producing natural sounding pitch contours in a speech synthesizer
First Claim
1. A method for synthesizing speech, comprising:
- generating a pitch contour for said synthesized speech; and
increasing an amount of energy in low frequency components of said pitch contour.
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Abstract
A speech synthesis system is disclosed that utilizes a pitch contour resulting in a more natural-sounding speech. The present invention modifies the predicted pitch, b(t), for synthesized speech using a low frequency energy booster. The low frequency energy booster interpolates the discrete pitch values, if necessary, and increase the amount of energy of the pitch contour associated with low frequency values, such as all frequency values below 10 Hertz. The amount of energy of the pitch contour associated with low frequency values can be increased, for example, by adding band-limited noise (a carrier signal) to the pitch contour, b(t), or by filtering the pitch values with an impulse response filter having a pole at the desired low frequency value. The present invention serves to add vibrato to the to the original pitch contour, b(t), and thereby improves the naturalness of the synthetic waveform.
24 Citations
24 Claims
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1. A method for synthesizing speech, comprising:
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generating a pitch contour for said synthesized speech; and
increasing an amount of energy in low frequency components of said pitch contour. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for synthesizing speech, comprising:
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generating a pitch contour for said synthesized speech; and
adding band limited noise to said pitch contour. - View Dependent Claims (11, 12, 13, 14, 15, 16, 18, 19, 20, 21)
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17. A method for synthesizing speech, comprising:
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generating a pitch contour for said synthesized speech; and
filtering said pitch contour with an impulse response filter having a pole at a desired low frequency value.
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22. A speech synthesizer, comprising:
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a pitch predictor that generates a pitch contour for said synthesized speech; and
a low frequency energy booster to increase an amount of energy in low frequency components of said pitch contour. - View Dependent Claims (23, 24)
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Specification