Speech codec
First Claim
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1. A speech codec, comprising:
- pitch extracting means for extracting a pitch-scale on the basis of a signal of an inputted speech;
voiced sound/unvoiced sound determinating means for determinating whether said inputted speech is one of a voiced sound speech and unvoiced sound speech on the basis of the signal of said inputted speech;
drive sound source generating means for generating a drive sound source signal on the basis of said pitch-scale and a determination result of said voiced sound/unvoiced sound determinating means, said drive sound source generating means including drive voiced sound source generating means for generating drive voiced sound source signal when said inputted speech is the voiced sound speech, and unvoiced sound source generating means for generating a drive unvoiced sound source signal when said inputted speech is the unvoiced sound speech, wherein said drive voiced sound source generating means includes pulse pattern generating means for generating a pulse pattern signal corresponding to said pitch-scale;
first adaptive code book means for storing drive voiced sound source signals within a predetermined past time period;
first noise code book means for storing in advance a noise signal; and
first generating means for generating the drive voiced sound source signal on the basis of said pulse pattern signal, an output of said first adaptive code book means and an output of said first noise code book means;
speech synthesizing means for outputting a synthesized speech signal on the basis of one of said drive voiced sound source signal and said drive unvoiced sound source signal generated by said drive sound source generating means; and
code outputting means for selectively outputting a code corresponding to one of said drive voiced sound source signal and said drive unvoiced sound source signal at a timing that an error between said synthesized speech signal and the signal of said inputted speech becomes minimum by comparing the synthesized speech signal and the signal of said inputted speech.
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Abstract
A speech codec includes a drive sound source generating circuit in which, in a case of a voiced sound speech, a pulse pattern signal corresponding to a pitch-scale, drive sound source signals stored within a newest predetermined past time period and a noise signal are multiplied by predetermined gains, respectively, and then, added to each other so as to generate a drive voiced sound source and, in a case of an unvoiced sound, drive sound source signals stored within a newest predetermined past time period and a noise signal are multiplied by predetermined gains, respectively, and then, added to each other so as to generate a drive unvoiced sound source.
20 Citations
18 Claims
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1. A speech codec, comprising:
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pitch extracting means for extracting a pitch-scale on the basis of a signal of an inputted speech; voiced sound/unvoiced sound determinating means for determinating whether said inputted speech is one of a voiced sound speech and unvoiced sound speech on the basis of the signal of said inputted speech; drive sound source generating means for generating a drive sound source signal on the basis of said pitch-scale and a determination result of said voiced sound/unvoiced sound determinating means, said drive sound source generating means including drive voiced sound source generating means for generating drive voiced sound source signal when said inputted speech is the voiced sound speech, and unvoiced sound source generating means for generating a drive unvoiced sound source signal when said inputted speech is the unvoiced sound speech, wherein said drive voiced sound source generating means includes pulse pattern generating means for generating a pulse pattern signal corresponding to said pitch-scale;
first adaptive code book means for storing drive voiced sound source signals within a predetermined past time period;
first noise code book means for storing in advance a noise signal; and
first generating means for generating the drive voiced sound source signal on the basis of said pulse pattern signal, an output of said first adaptive code book means and an output of said first noise code book means;speech synthesizing means for outputting a synthesized speech signal on the basis of one of said drive voiced sound source signal and said drive unvoiced sound source signal generated by said drive sound source generating means; and code outputting means for selectively outputting a code corresponding to one of said drive voiced sound source signal and said drive unvoiced sound source signal at a timing that an error between said synthesized speech signal and the signal of said inputted speech becomes minimum by comparing the synthesized speech signal and the signal of said inputted speech. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A speech codec, comprising:
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pitch extracting means for extracting pitch-scale on the basis of a signal of an inputted speech; analyzing means for analyzing a parameter of said inputted speech; first speech synthesizing means for synthesizing a voiced sound synthesized speech signal on the basis of said pitch-scale and said parameter, wherein said first speech synthesizing means includes pulse pattern generating means for generating a pulse pattern signal in response to said pitch-scale;
first adaptive code book means for storing a drive voiced sound source signal within a predetermined past time period;
first noise code book means for storing in advance a noise signal; and
first generating means for generating said voiced sound synthesized speech signal on the basis of said pulse pattern signal, an output of said first adaptive code book means and an output of said first noise code book means;second speech synthesizing means for synthesizing an unvoiced sound synthesized speech signal on the basis of the signal of said inputted speech and said parameter; similarity determining means for determining that which one of said voiced sound synthesized speech signal and unvoiced sound synthesized speech signal is similar to said inputted speech; selecting means for selecting one of said voiced sound synthesized speech signal and said unvoiced sound synthesized speech signal in response to an output of said similarity determining means; and multiplexer means for multiplexing one of said voiced sound synthesized speech signal and said unvoiced sound synthesized speech signal selected by said selecting means and said parameter. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification