US4716592A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for encoding voice signals
Assignee: NEC Corp
•
Filing: 1983-12-27
•
Granted: 1987-12-29
•
Expires: 2003-12-27
Abstract
Abstract A voice encoding system is constituted by a short time voice signal series producing circuit inputted with a discrete voice signal series for dividing the same at each short time; a parameter extracting circuit for extracting a parameter representative of a spectrum envelope from the short time voice signal series and encoding the parameter; an impulse response series calculating circuit for calculating the impulse response series based on the parameter representative of the spectrum envelope; an autocorrelation function sequence calculating circuit utilizing the impulse response series; a cross-correlation function sequence calculating circuit utilizing the impulse response series and the short time voice signal series; a circuit for calculating and encoding an excitation signal series of the short time voice signal series by utilizing the autocorrelation function sequence; and a circuit for combining and outputting a code of the parameter representative of the spectrum envelope and a code representative of the excitation signal series. With the system, high quality voice encoding can be made at a transmission rate of less than 10k bits/second with a relatively small amount of calculation.
Inventors
- 👤 Kazunori Ozawa
- 👤 Takashi Araseki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:05
CPC Classifications
G; G10; G10L; G10L19/00; G10L19/04; G10L19/08; G10L19/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
153 words
An apparatus for encoding voice signals comprising: means inputted with a discrete voice signal series for dividing said voice signal series at each time interval to obtain a time interval voice signal series; means for extracting a parameter representative of a spectrum envelope from said time interval voice signal series and encoding the parameter; means for calculating an impulse response series based on said parameter representative of said spectrum envelope; means for calculating an autocorrelation function sequence of said impulse response series; means for calculating a cross-correlation function sequence between said impulse response series and said time interval voice signal series; means for calculating and encoding an excitation signal series of said time interval voice signal series by using said autocorrelation function sequence and said cross-correlation function sequence; and means for combining and outputting a code of said parameter representative of said spectrum envelope and a code representative of said excitation signal series.
Claim 2
Independent Claim
153 words
An apparatus for encoding voice signals comprising: means inputted with a discrete voice signal series for dividing said voice signal series at each time interval to obtain a time interval voice signal series; means for extracting a parameter representative of a spectrum envelope from said time interval voice signal series and encoding the parameter; means for calculating an impulse response series based on said parameter representative of said spectrum envelope; means for calculating an autocorrelation function sequence of said impulse response series; means for calculating a cross-correlation function sequence between said impulse response series and said time interval voice signal series; means for calculating and encoding an excitation signal series of said time interval voice signal series by using said autocorrelation function sequence and said cross-correlation function sequence; and means for combining and outputting a code of said parameter representative of said spectrum envelope and a code representative of said excitation signal series.
Claim 3
Independent Claim
193 words
An apparatus for encoding voice signals comprising: means inputted with a discrete voice signal series for dividing said voice signal series at each time interval to obtain a time interval voice signal series; means for extracting a parameter representative of a spectrum envelope from said short time voice signal series and encoding the parameter; means for calculating an impulse response series based on a spectrum envelope parameter which is said parameter representative of said spectrum envelope subjected to a predetermined correction based on said time interval voice signal series; means for calculating an autocorrelation function sequence of said impulse response series; means for calculating a target signal series which has been subjected to said predetermined correction based on said time interval voice signal series; means for calculating a cross-correlation function sequence between said impulse response series and said target signal series; means for calculating and encoding an excitation signal series of said time interval voice signal series by using said autocorrelation function series and said cross-correlation function series; and means for combining and outputting a code of said parameter representative of said spectrum envelope and a code representative of said excitation signal series.
Claim 4
Independent Claim
193 words
An apparatus for encoding voice signals comprising: means inputted with a discrete voice signal series for dividing said voice signal series at each time interval to obtain a time interval voice signal series; means for extracting a parameter representative of a spectrum envelope from said short time voice signal series and encoding the parameter; means for calculating an impulse response series based on a spectrum envelope parameter which is said parameter representative of said spectrum envelope subjected to a predetermined correction based on said time interval voice signal series; means for calculating an autocorrelation function sequence of said impulse response series; means for calculating a target signal series which has been subjected to said predetermined correction based on said time interval voice signal series; means for calculating a cross-correlation function sequence between said impulse response series and said target signal series; means for calculating and encoding an excitation signal series of said time interval voice signal series by using said autocorrelation function series and said cross-correlation function series; and means for combining and outputting a code of said parameter representative of said spectrum envelope and a code representative of said excitation signal series.
Claim 5
Independent Claim
309 words
A method of encoding voice signals comprising the steps of: inputting a discrete voice signal series on a transmission side; dividing said voice signal series at each time interval to obtain a time interval voice signal series; subtracting a response signal series synthesized by a determined excitation signal series in a time interval voice signal series previous to said time interval voice signal series and forming a target signal series based on the result of said subtraction; extracting and encoding a parameter representative of a spectrum envelope of one of said time interval voice signal series and a spectrum envelope of the result of said subtraction; determining an impulse response series based on the parameter representative of said spectrum envelope and calculating an autocorrelation function sequence of said impulse response series; determining and encoding an excitation signal series of said voice signal series by using said autocorrelation function sequence and said cross-correlation function sequence; forming a response signal series originating from said excitation signal series; combining and outputting a code series of parameter representative of said spectrum envelope and a code series of said excitation signal series; inputting said code series on a receiving side and separating said code series of said excitation signal series and said code series of said parameter representative of said spectrum envelope; decoding said excitation signal series from said separated code series and producing an excitation signal series; decoding said separated code series of said parameter representative of said spectrum envelope; synthesizing a voice signal series by using said decoded parameter and said produced excitation signal series; calculating a response signal series synthesized by a decoded excitation signal series for a time interval voice signal series previous to said time interval voice signal series; and adding together said response signal series and said synthesized voice signal series to output the result of said addition.
Claim 6
Independent Claim
309 words
A method of encoding voice signals comprising the steps of: inputting a discrete voice signal series on a transmission side; dividing said voice signal series at each time interval to obtain a time interval voice signal series; subtracting a response signal series synthesized by a determined excitation signal series in a time interval voice signal series previous to said time interval voice signal series and forming a target signal series based on the result of said subtraction; extracting and encoding a parameter representative of a spectrum envelope of one of said time interval voice signal series and a spectrum envelope of the result of said subtraction; determining an impulse response series based on the parameter representative of said spectrum envelope and calculating an autocorrelation function sequence of said impulse response series; determining and encoding an excitation signal series of said voice signal series by using said autocorrelation function sequence and said cross-correlation function sequence; forming a response signal series originating from said excitation signal series; combining and outputting a code series of parameter representative of said spectrum envelope and a code series of said excitation signal series; inputting said code series on a receiving side and separating said code series of said excitation signal series and said code series of said parameter representative of said spectrum envelope; decoding said excitation signal series from said separated code series and producing an excitation signal series; decoding said separated code series of said parameter representative of said spectrum envelope; synthesizing a voice signal series by using said decoded parameter and said produced excitation signal series; calculating a response signal series synthesized by a decoded excitation signal series for a time interval voice signal series previous to said time interval voice signal series; and adding together said response signal series and said synthesized voice signal series to output the result of said addition.
Claim 7
Dependent Claim
352 words
An encoding and decoding apparatus comprising: a subtracting circuit inputted with a discrete voice signal series and subtracting a response signal series from said voice signal series; a parameter calculating circuit extracting and encoding a parameter representative of a spectrum envelope of one of said time interval voice signal series and a spectrum envelope of the output series of said subtracting circuit; an impulse response series calculating circuit for calculating an impulse response series by subjecting said parameter representative of said spectrum envelope to a predetermined correction; an autocorrelation function sequence calculating circuit inputted with the output series of said impulse response series calculating circuit for calculating an autocorrelation function sequence; a cross-correlation function calculating circuit for calculating a cross-correlation function sequence between said impulse response series and a signal series obtained by subjecting said output series of said subtracting circuit to said predetermined correction; an excitation signal series calculating circuit inputted with said autocorrelation function sequence and said cross-correlation function sequence for calculating and encoding said excitation signal series of said voice signal series; a response signal series calculating circuit inputted with said excitation signal series for calculating said response signal rates series originating from said excitation signal series; a multiplexer circuit for combining and outputting the output code series of said parameter calculating circuit and the code series of said excitation signal series; a demultiplexer circuit inputted with a code series formed by combining an output code series of a parameter calculating circuit and a code series of said excitation signal series for separating a code series representative of said excitation signal series and a code series of a parameter representative of said spectrum envelope; an excitation pulse series generating circuit for decoding said separated code series representative of said excitation signal series for generating an excitation series; a decoding circuit for decoding said separated code series of said parameter representative of said spectrum envelope; and a synthesizing filter circuit inputted with the output series of said excitation signal series generating circuit for synthesizing and outputting a voice signal serie s by using the output parameter of said decoding circuit.
Claim 8
Dependent Claim
352 words
An encoding and decoding apparatus comprising: a subtracting circuit inputted with a discrete voice signal series and subtracting a response signal series from said voice signal series; a parameter calculating circuit extracting and encoding a parameter representative of a spectrum envelope of one of said time interval voice signal series and a spectrum envelope of the output series of said subtracting circuit; an impulse response series calculating circuit for calculating an impulse response series by subjecting said parameter representative of said spectrum envelope to a predetermined correction; an autocorrelation function sequence calculating circuit inputted with the output series of said impulse response series calculating circuit for calculating an autocorrelation function sequence; a cross-correlation function calculating circuit for calculating a cross-correlation function sequence between said impulse response series and a signal series obtained by subjecting said output series of said subtracting circuit to said predetermined correction; an excitation signal series calculating circuit inputted with said autocorrelation function sequence and said cross-correlation function sequence for calculating and encoding said excitation signal series of said voice signal series; a response signal series calculating circuit inputted with said excitation signal series for calculating said response signal rates series originating from said excitation signal series; a multiplexer circuit for combining and outputting the output code series of said parameter calculating circuit and the code series of said excitation signal series; a demultiplexer circuit inputted with a code series formed by combining an output code series of a parameter calculating circuit and a code series of said excitation signal series for separating a code series representative of said excitation signal series and a code series of a parameter representative of said spectrum envelope; an excitation pulse series generating circuit for decoding said separated code series representative of said excitation signal series for generating an excitation series; a decoding circuit for decoding said separated code series of said parameter representative of said spectrum envelope; and a synthesizing filter circuit inputted with the output series of said excitation signal series generating circuit for synthesizing and outputting a voice signal serie s by using the output parameter of said decoding circuit.
Claim 9
Dependent Claim
340 words
An encoding and decoding apparatus comprising: a subtracting circuit inputted with a discrete voice signal series and subtracting a response signal series from said voice signal series; a parameter calculating circuit extracting and encoding a parameter representative of a spectrum envelope of one of said time interval voice signal series and a spectrum envelope of the output series of said subtracting circuit; an impulse response series calculating circuit for calculating an impulse response series from said parameter representative of said spectrum envelope; an autocorrelation function sequence calculating circuit inputted with the output series of said impulse response series calculating circuit for calculating an autocorrelation function sequence; a cross-correlation function calculating circuit for calculating a cross-correlation function sequence between said impulse response series and a signal series obtained from said output series of said subtracting circuit; an excitation signal series calculating circuit inputted with said autocorrelation function sequence and said cross-correlation function sequence for calculating and encoding said excitation signal series of said voice signal series; a response signal series calculating circuit inputted with said excitation signal series for calculating said response signal series originating from said excitation signal series; a multiplexer circuit for combining and outputting the output code series of said parameter calculating circuit and the code series of said excitation signal series; a demultiplexer circuit inputted with a code series formed by combining an output code series of a parameter calculating circuit and a code series of said excitation signal series for separating a code series representative of said excitation signal series and a code series of a parameter representative of said spectrum envelope; an excitation pulse series generating circuit for decoding said separated code series representative of said excitation signal series for generating an excitation series; a decoding circuit for decoding said separated code series of said parameter representative of said spectrum envelope; and a synthesizing filter circuit inputted with the output series of said excitation signal series generating circuit for synthesizing and outputting a voice signal series by using the output parameter of said decoding circuit.
Claim 10
Dependent Claim
340 words
An encoding and decoding apparatus comprising: a subtracting circuit inputted with a discrete voice signal series and subtracting a response signal series from said voice signal series; a parameter calculating circuit extracting and encoding a parameter representative of a spectrum envelope of one of said time interval voice signal series and a spectrum envelope of the output series of said subtracting circuit; an impulse response series calculating circuit for calculating an impulse response series from said parameter representative of said spectrum envelope; an autocorrelation function sequence calculating circuit inputted with the output series of said impulse response series calculating circuit for calculating an autocorrelation function sequence; a cross-correlation function calculating circuit for calculating a cross-correlation function sequence between said impulse response series and a signal series obtained from said output series of said subtracting circuit; an excitation signal series calculating circuit inputted with said autocorrelation function sequence and said cross-correlation function sequence for calculating and encoding said excitation signal series of said voice signal series; a response signal series calculating circuit inputted with said excitation signal series for calculating said response signal series originating from said excitation signal series; a multiplexer circuit for combining and outputting the output code series of said parameter calculating circuit and the code series of said excitation signal series; a demultiplexer circuit inputted with a code series formed by combining an output code series of a parameter calculating circuit and a code series of said excitation signal series for separating a code series representative of said excitation signal series and a code series of a parameter representative of said spectrum envelope; an excitation pulse series generating circuit for decoding said separated code series representative of said excitation signal series for generating an excitation series; a decoding circuit for decoding said separated code series of said parameter representative of said spectrum envelope; and a synthesizing filter circuit inputted with the output series of said excitation signal series generating circuit for synthesizing and outputting a voice signal series by using the output parameter of said decoding circuit.
References Cited (Backward Citations)
US4544919A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-12-28 | 1991-06-29 | 1991-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-28 | 1995-06-29 | 1995-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-28 | 1999-06-29 | 1999-12-29 | $7700.00 | Window Closed / Lapsed |