Device and method for estimating harmonics in voice encoder
First Claim
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1. A harmonic estimating method comprising:
- applying a window spectrum to an input signal, performing fast Fourier transformation of a predetermined amplitude on a generated spectrum, and calculating an input signal spectrum;
generating a synthesized signal spectrum of a fractional pitch candidate using the window spectrum scaled by a first basic frequency, harmonic amplitude, and high frequency signal amplitude;
calculating error energy of the input signal spectrum and the synthesized signal spectrum on each frequency band, and calculating a second basic frequency at which the error energy is minimized; and
calculating maximum harmonic amplitude at the second basic frequency.
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Abstract
The present invention relates to methods and devices for estimating harmonics that reduce the calculation amount and can be used very effectively in a low transmission rate voice encoder by adjusting a harmonic interval with centering on a multiple of a basic frequency or extracting a peak so that the error between an original signal spectrum and estimated harmonic spectrum is reduced.
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Citations
29 Claims
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1. A harmonic estimating method comprising:
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applying a window spectrum to an input signal, performing fast Fourier transformation of a predetermined amplitude on a generated spectrum, and calculating an input signal spectrum;
generating a synthesized signal spectrum of a fractional pitch candidate using the window spectrum scaled by a first basic frequency, harmonic amplitude, and high frequency signal amplitude;
calculating error energy of the input signal spectrum and the synthesized signal spectrum on each frequency band, and calculating a second basic frequency at which the error energy is minimized; and
calculating maximum harmonic amplitude at the second basic frequency. - View Dependent Claims (2)
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3. A harmonic estimating method comprising:
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applying a window spectrum to an input signal, performing fast Fourier transformation of amplitude of N1 on a generated spectrum, and calculating an input signal spectrum;
applying a window spectrum scaled by harmonic amplitude to an integer pitch candidate, performing fast Fourier transformation of amplitude of N2 on a generated spectrum, and calculating a synthesized signal spectrum;
calculating an adjustment value of a high frequency at which error energy of the input signal spectrum and the synthesized signal spectrum for each band is minimized in range of the adjustment value of a harmonic frequency using the integer pitch candidate; and
calculating maximum harmonic amplitude by using the adjustment value of the high frequency at which the error energy for each band is minimized. - View Dependent Claims (4, 5, 6, 7)
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8. A harmonic estimating device comprising:
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a harmonic frequency adjusting means for calculating a range of a harmonic frequency adjustment value using an integer unit pitch, and for selecting a frequency adjustment value at which error energy is minimized by using the harmonic frequency adjustment value belonging to the range; and
a harmonic amplitude estimating means for estimating a maximum harmonic amplitude by harmonics using the harmonic frequency adjustment value at which the error energy is minimized, the harmonic frequency adjustment value being found by the harmonic frequency adjusting means. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A harmonic estimating device comprising:
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a means for calculating an input signal spectrum of an input signal, and applying window spectrum to an integer pitch candidate, and a synthesized signal spectrum;
a means for extracting a peak point from each harmonic band, and calculating a limit value of frequency adjustment of each harmonic band;
a means for calculating error energy of the input signal spectrum and the synthesized signal spectrum for each band by using the limit value of frequency adjustment and the peak point;
a means for calculating a harmonic frequency adjustment value at which the error energy is minimized; and
a means for calculating a harmonic amplitude using the harmonic frequency adjustment value and the peak point. - View Dependent Claims (15)
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16. A harmonic estimating method comprising:
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generating an input signal spectrum;
generating a synthesized signal spectrum;
calculating an adjustment value within a range of adjustment values at which error energy of the input signal spectrum and the synthesized signal spectrum for each band is minimized; and
estimating a maximum harmonic amplitude for each band by using the adjustment value for each band. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. A harmonic estimating device comprising:
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a harmonic frequency adjuster that calculates a range of harmonic frequency adjustment values, and that selects a harmonic frequency adjustment value within the range at which error energy is minimized for each band; and
a harmonic amplitude estimator that estimates a maximum harmonic amplitude for each band using the harmonic frequency adjustment value at which the error energy is minimized. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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Specification