Encoder capable of removing interaction between adjacent frames
First Claim
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1. An encoder for encoding an input signal into an encoded signal by the use of an autocorrelaton signal and a cross-correlation signal which are internally produced to specify autocorrelation and cross-correlation related to said input signal, respsectively, said input signal carrying a plurality of speech samples placed within both of a current frame and a part of a following frame, said encoder comprising:
- impulse response deriving means responsive to said input signal for deriving an impulse response from said plurality of the speech samples of said input signal to produce an impulse response signal representative of said impulse response;
cross-correlation calculating means responsive to said input signal and said impulse response signal for calculating cross-correlation between said input signal and said impulse response signal in relation to said plurality of the speech samples for said current frame and said part of the following frame to produce a cross-correlation signal representative of the cross-correlation between said input signal and said impulse response signal;
autocorrelation calculating means coupled to said impulse response deriving means for calculating autocorrelation of said impulse response signal to produce an autocorrelaton signal representative of said autocorrelation;
control signal producing means responsive to said encoded signal and said autocorrelation signal for producing a control signal related to the autocorrelation of said part of the following frame;
subtracting means coupled to said cross-correlation calculating means and said control signal producing means for subtracting said control signal from said cross-correlation signal to produce a difference signal representative of a difference between said cross-correlation signal and said control signal, said difference signal being produced for said part of the following frame; and
processing means coupled to said subtracting means and said autocorrelation calculating means for processing said difference signal and said auto-correlation signal into said encoded signal produced only for said current frame.
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Abstract
In a multipulse pitch speech excitation generator, pulses which may everlap the next frame are eliminated by a subtraction process (CC-HH), and pulses from the next frame which may overlap the present frame are eliminated by selection.
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3 Claims
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1. An encoder for encoding an input signal into an encoded signal by the use of an autocorrelaton signal and a cross-correlation signal which are internally produced to specify autocorrelation and cross-correlation related to said input signal, respsectively, said input signal carrying a plurality of speech samples placed within both of a current frame and a part of a following frame, said encoder comprising:
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impulse response deriving means responsive to said input signal for deriving an impulse response from said plurality of the speech samples of said input signal to produce an impulse response signal representative of said impulse response; cross-correlation calculating means responsive to said input signal and said impulse response signal for calculating cross-correlation between said input signal and said impulse response signal in relation to said plurality of the speech samples for said current frame and said part of the following frame to produce a cross-correlation signal representative of the cross-correlation between said input signal and said impulse response signal; autocorrelation calculating means coupled to said impulse response deriving means for calculating autocorrelation of said impulse response signal to produce an autocorrelaton signal representative of said autocorrelation; control signal producing means responsive to said encoded signal and said autocorrelation signal for producing a control signal related to the autocorrelation of said part of the following frame; subtracting means coupled to said cross-correlation calculating means and said control signal producing means for subtracting said control signal from said cross-correlation signal to produce a difference signal representative of a difference between said cross-correlation signal and said control signal, said difference signal being produced for said part of the following frame; and processing means coupled to said subtracting means and said autocorrelation calculating means for processing said difference signal and said auto-correlation signal into said encoded signal produced only for said current frame. - View Dependent Claims (2, 3)
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Specification