System for synthesizing speech having fluctuation

• US 5,007,095 A
• Filed: 12/29/1989
• Issued: 04/09/1991
• Est. Priority Date: 03/18/1987
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Nara, Yasuhiro, Matsumoto, Tatsuro
• Primary Examiner(s): Shaw, Dale M.
• Assistant Examiner(s): Knepper, David D.
• Application Number:
  US07/462,295
• Time in Patent Office: 466 Days
• Field of Search: 364/513.5, 364/714.17, 381/51-53
• US Class Current: 704/261
• CPC Class Codes: G10L 13/08 Text analysis or generation of parameters for speech synthesis out of text, e.g. grapheme to phoneme translation, prosody generation or stress or intonation determination

Abstract

A system for synthesizing speech having improved naturalness and formed by a simple construction. The speech synthesizing system includes a unit for generating a vowel signal, a unit for generating a consonant signal including a unit for generating random data, a unit connected to the random data generating unit for receiving the random data therefrom, and having a first-order delaying function 1/(sτ α). The unit having a first-order delay for receiving the random data outputs first-order delayed random data. A unit for selecting the vowel signal or the consonant signal in response to a selection signal and a unit for receiving an output signal from the selection unit and filtering the received signal on the basis of a vocal tract simulation method are also provided. The first-order delayed random data from the first-order delaying unit are substantially applied to the vowel signal and/or the consonant signal.

Claims

1. A speech synthesizing system, comprising:

means for generating a vowel signal;

means for generating a consonant signal;

means for generating random data;

fluctuation data generating means, operatively connected to said random data generating means, for receiving random data from said means for generating random data, having a first-order delaying function for outputting fluctuation data, said fluctuation data generating means comprising;

first adding means having an input terminal and connected to said means for generating random data;

integral means, connected to said first adding means, for receiving an output from said first adding means and having an output terminal, said integral comprising;

multiplying means connected to said first adding means;

second adding means connected to said multiplying means and including an input terminal;

data holding means connected to said second adding means and having an input terminal; and

feedback line means provided between the output terminal of said data holding means and the input terminal of said second adding means, said multiplying means multiplying the output from said first adding means of said fluctuation data generating means and a factor of 1/τ

, where τ

is a time constant, and said second adding means in said integral means adding the output from said multiplying means and the output from said data holding means through said feedback line means;

negative feedback means, connected between the output terminal of said integral means and the input terminal of said first adding means, for multiplying the output from said integral means and a coefficient and inverting a signal of the multiplied value, said first adding means adding random data from said random data generating means and the inverted multiplied value from said negative feedback means;

selecting means, connected to receive a selection signal, for selecting one of the vowel signal or the consonant signal in response to the selection signal; and

means, operatively connected to said selecting means, for receiving an output signal from said selecting means and for filtering the received signal on the basis of a vocal tract simulation method, the fluctuation data from said fluctuation data generating means being substantially multiplied or added to one of the vowel signal or the consonant signal as determined by said selecting means.

2. A speech synthesizing system according to claim 1, wherein said coefficient is one.

3. A speech synthesizing system according to claim 1, wherein said vowel signal generating means and said consonant signal generating means comprise a common parameter interposing means for receiving a first signal having a sound frequency, a second signal having a voice amplitude and a third signal having a voiceless amplitude, and interposing the received first to third signals to output first to third interposed signals;

wherein said vowel signal generating means further comprises;

means for generating an impulse train signal in response to the first interposed signal;

means, connected to said impulse train signal generating means, for multiplying the impulse train signal and the second interposed signal, and for supplying a first multiplied signal to said selection means;

means for adding a constant as a bias and the first-order delayed random data from said first-order delaying means; and

means, connected to said means for adding a constant, for multiplying an added signal from said means for adding a constant and the output from said vocal tract simulation filtering means and for outputting a speech signal having fluctuation components; and

wherein said consonant signal generating means further comprises means for multiplying the random data output from said random data generation means and the third interposed signal to supply a second multiplied signal to said selection means.

4. A speech synthesizing system according to claim 3, wherein said common parameter interposing means comprises linear interposing means.

5. A speech synthesizing system according to claim 3, wherein said common parameter interposing means comprises:

first data holding means;

critical damping two-order filtering means connected in series with said first data holding means; and

second data holding means connected in series with said critical damping two-order filtering means.

6. A speech synthesizing system according to claim 5, wherein said critical damping two-order filtering means comprises:

first and second adder means connected in series;

first integral means connected to said second adder means and having an output terminal;

first multiplying means, connected between the output terminal of said first integral means and an input terminal of said second adder means, for multiplying the output of said first integral means and a damping factor and inverting a sign of the multiplied value;

second integrator means connected to said first integrator means and having an output terminal; and

second multiplying means, connected between the output terminal of said second integral means and an input terminal of said first adding means, for multiplying an output from said second integral means and a coefficient, and inverting a signal of the multiplied value,

said first adding means adding an output from said first data holding means of said common parameter interposing means and the inverted multiplied value from said second multiplying means, and

said second adding means adding an output from said first adding means and the inverted multiplied value from said first multiplying means.

7. A speech synthesizing system according to claim 6, wherein each of said first and second integral means comprises:

third multiplying means connected to said first adding means;

fourth adding means having an input terminal and connected to said third multiplying means;

data holding means having an output terminal and connected to said fourth adding means; and

feedback line means provided between the output terminal of said data holding means and the input terminal of said fourth adding means,

said third multiplying means multiplying the input signal and a factor 1/τ

, where τ

is a time constant, and

said fourth adding means adding the output from said third multiplying means and the output from said data holding means through said feedback line means.

8. A speech synthesizing system according to claim 7, wherein the damping factor DF is two, and the coefficient is one.

9. A speech synthesizing system according to claim 5, wherein said critical damping two-order filtering means comprises:

first and second first-order delaying means connected in series, each including;

adding means having an input terminal;

integral means having an output terminal and connected to said adding means; and

multiplying means provided between the output terminal of said integral means and the input terminal of said adding means, for multiplying an output of said adding means, for multiplying an output of said integral means and the coefficient and inverting the product,

said adding means adding the input and the inverted-multiplied value from said multiplying means and supplying the sum to said integral means.

10. A speech synthesizing system according to claim 9, wherein said integral means comprises:

multiplying means;

adding means connected to said multiplying means and having an input-terminal;

data holding means connected to said adding means and having an output terminal; and

feedback line means provided between the output terminal of said data holding means and the input terminal of said adding means,

said multiplying means multiplying the input signal and a factor 1/τ

, where τ

is a time constant, and

said adding means adding an output from said adding means and the output from said data holding means through said feedback line means.

11. A speech synthesizing system according to claim 10, wherein the coefficient is one.

12. A speech synthesizing system according to claim 1, further comprising means for adding a constant as a bias to the fluctuation data from said fluctuation data generating means;

wherein said vowel signal generating means and said consonant signal generating means comprise a common parameter interposing means for receiving a first signal having a sound frequency, a second signal having a voice amplitude and a third signal having a voiceless amplitude, and interposing the received first to third signals to output first to third interposed signals;

wherein said vowel signal generating means further comprises;

first multiplying means, connected to said common parameter interposing means, for multiplying the first interposed signal and the added signal from said first adding means;

means, connected to said first multiplying means, for generating an impulse train signal in response to the multiplied signal from said first multiplying means;

second multiplying means, connected to said common parameter interposing means, for multiplying the second interposed signal and the added signal from said first adding means; and

third multiplying means, connected to said impulse train generating means and said second multiplying means, for multiplying the impulse train signal and the second multiplied signal from said second multiplying means and for outputting the multiplied signal to said selection means; and

wherein said constant signal generating means further comprises;

fourth multiplying means, connected to said first adding means, for multiplying the added signal from said first adding means and the third interposed signal; and

fifth multiplying means, connected to said random data generating means, for multiplying the random signal from said random data generating means and the fifth multiplied signal from said fifth multiplying means to supply the fifth multiplied signal to said selection means.

13. A speech synthesizing system according to claim 12, wherein the common parameter interposing means comprises linear interposing means.

14. A speech synthesizing system according to claim 12, wherein the common parameter interposing means comprises series-connected first data holding means, critical damping two-order filtering means and second data holding means.

15. A speech synthesizing system according to claim 1, wherein said vowel signal generating means and said consonant signal generating means comprise a common parameter interposing means for receiving a first signal having a sound frequency, a second signal having a voice amplitude and a third signal having a voiceless amplitude, and interposing the received first to third signals to output first to third interposing signals;

wherein said vowel signal generating means further comprises;

first adding means, connected to said first-order delaying means and said common parameter interposing means, for adding the first interposed signal and the fluctuation data from said fluctuation data generating means;

means, connected to said first adding means, for generating an impulse train signal in response to the first added signal from said first adding means;

second adding means, connected to said common parameter interposing means and said fluctuation data generating means, for adding the second interposed signal and the first-order delayed signal; and

first multiplying mans, connected to said impulse train generating means and said second adding means, for multiplying the impulse train signal and the second added signal from said second adding means, and for outputting the first multiplied signal to said selection means; and

wherein said consonant signal generating means further comprises;

third adding means, connected to said common parameter interposing means and said fluctuation data generating means, for adding the third interposed signal and the first-order delayed signal; and

second multiplying means, connected to said random data generating means and said third adding means, for multiplying the random data from said random data generating means and the third added signal from said third adding means, and for outputting the second multiplied signal to said selection means.

16. A speech synthesizing system according to claim 15, wherein the common parameter interposing means comprises linear interposing means.

17. A speech synthesizing system according to claim 15, wherein the common parameter interposing means comprises series-connected first data holding means, critical damping two-order filtering means and second data holding means.

18. A speech synthesizing system comprising:

parameter interpolating means;

impulse train generating means having an input and an output terminal and connected to said parameter interpolating means;

random data generating means, connected to said parameter interpolating means, for generating random data and having an output terminal;

selection means having two input terminals and an output terminal, for generating a selection signal for selecting one of said impulse train generating means and said random data generating means;

first multiplying means connected between the output terminal of said impulse train generating means and a first one of the input terminals of said selection means;

second multiplying means connected between the output terminal of said random data generation means and a second one of the input terminals of said selection means; and

means, connected to the output terminal of said selection means, for filtering an output from said selection means on the basis of a vocal tract simulation method,

said parameter interpolating means including;

critical damping two-order filtering means, operatively connected to said random data generating means, for receiving the random data from said random data generating means, and for interpolating a first signal having a sound frequency, a second signal having a sound amplitude and a third signal having a silent amplitude by multiplying the random data with the first, second and third signals and by filtering the first through third multiplied data using a critical damping two-order filtering method, to output the first through third interpolated signals,

said impulse train generating means generating impulse trains in response to the first interpolated signal,

said first multiplying means multiplying the impulse trains and the second interpolated signal and outputting a vowel signal to the first one of the input terminals of said selection means;

said second multiplying means multiplying the random data and the third interpolated signal and outputting a consonant signal to the second one of the input terminals of said selection means; and

said selection means selecting one of the vowel signal and consonant signal, and outputting a selected signal to said vocal tract simulation filtering means.

19. A speech synthesizing system according to claim 18, wherein said critical damping two-order means in said parameter interpolating means comprises:

first multiplying means for multiplying the input and a first coefficient;

first adding means, connected to said first multiplying means and having an input terminal;

second adding means, connected to said first adding means and having an output terminal;

first integral means, connected to the out put terminal of said second adding means, and having an output terminal;

second multiplying means, connected between the output terminal of said first integral means and the input terminal of said second adding means for multiplying an output of said first integral means and a second coefficient and for outputting the product to said second adding means;

second integral means, connected to the output terminal of said first integral means and having an output terminal; and

third multiplying means, provided between the output terminal of said second integral means and the input terminal of said first adding means and for multiplying an output from said second integral means and a third coefficient,

said first adding means adding an output from said first multiplying means and an output from said third multiplying means, and

said second adding means adding an output from said first adding means and an output from said second multiplying means, and outputting the interpolated signals.

20. A speech synthesizing system according to claim 19, wherein each of said first and second integral means comprises:

multiplying means;

adding means connected to said multiplying means and having an input terminal;

data holding means connected to said adding means and having an output terminal; and

feedback line means provided between the output terminal of said data holding means and the input terminal of said adding means,

said multiplying means multiplying the input and a factor 1/τ

, where τ

is a time constant, and

said adding means adding the output from said multiplying means and the output from said data holding means through said feedback line means.

21. A speech synthesizing system according to claim 20, wherein the damping factor DF is two, and the coefficient is one.

22. A speech synthesizing system according to claim 19, wherein each of said first and second integral means comprises:

a first adder connected to receive the input;

first multiplying means connected to said first adder;

a second adder connected to said first multiplying means;

a delay element connected to said second adder;

a feedback line connected between an output terminal of said delay element and the input of said second adder; and

second multiplying means connected between the output terminal of said delay element and said first adder.