US5457783A — Adaptive speech coder having code excited linear …

Claim 1

Independent Claim 167 words

Apparatus for determining a codeword in a speech coder which codes a speech signal, which speech coder determines a target signal formed in response to filtering said speech signal to remove ringing information and pitch information and which speech coder determines a linear prediction coefficient synthesis filter in response to said speech signal, said apparatus comprising: impulse response means for determining the impulse response of said synthesis filter; a first filter for filtering said target signal with said impulse response thereby forming a search signal; position locator for locating within said search signal the position of the largest positive and largest negative values; and formation means for forming a codeword comprising a series of values, wherein all values in the codeword are zero except for a first value and a second value, wherein said first value is positioned in said codeword in response to the position of said largest positive value and said second value is positioned in response to the position of said largest negative value.

Claim 2

Dependent Claim 167 words

Apparatus for determining a codeword in a speech coder which codes a speech signal, which speech coder determines a target signal formed in response to filtering said speech signal to remove ringing information and pitch information and which speech coder determines a linear prediction coefficient synthesis filter in response to said speech signal, said apparatus comprising: impulse response means for determining the impulse response of said synthesis filter; a first filter for filtering said target signal with said impulse response thereby forming a search signal; position locator for locating within said search signal the position of the largest positive and largest negative values; and formation means for forming a codeword comprising a series of values, wherein all values in the codeword are zero except for a first value and a second value, wherein said first value is positioned in said codeword in response to the position of said largest positive value and said second value is positioned in response to the position of said largest negative value.

Claim 3

Dependent Claim 17 words

The apparatus of claim 1, wherein said first value is +1 and said second value is -1.

Claim 4

Dependent Claim 33 words

The apparatus of claim 1, wherein said impulse response comprises a series of impulse response values and wherein said impulse response means comprises truncation means for truncating the number of impulse response values.

Claim 5

Dependent Claim 34 words

The apparatus of claim 3, further comprising gain means for determining a gain value in conjunction with said codeword, wherein said gain means calculates said gain value in relation to the full impulse response.

Claim 6

Dependent Claim 23 words

The apparatus of claim 1, further comprising transform means for transforming said codeword, wherein said codeword is determined in relation to being transformed.

Claim 7

Dependent Claim 12 words

The apparatus of claim 5, wherein said transform is a Hadamard transform.

Claim 8

Dependent Claim 144 words

A speech coder for converting analog speech signals to digital speech signals for transmission, wherein a backward filtered target vector is provided, said speech coder comprising: a first filter for filtering out the spectral information from said speech signal and for providing said spectral information for transmission; a second filter for filtering out the pitch information from said speech signal and for providing said pitch information for transmission; and a codevector generator for determining the characteristics of a bi-pulse codevector representative of the speech signal after said spectral information and said pitch information have been filtered out and for providing said characteristics for transmission, wherein the determination of said characteristics is made by only analyzing the correlation between each possible bi-pulse codevector and said backward filtered target vector, wherein said codevector generator examines said correlation to determine the largest positive and largest negative values.

Claim 9

Dependent Claim 144 words

A speech coder for converting analog speech signals to digital speech signals for transmission, wherein a backward filtered target vector is provided, said speech coder comprising: a first filter for filtering out the spectral information from said speech signal and for providing said spectral information for transmission; a second filter for filtering out the pitch information from said speech signal and for providing said pitch information for transmission; and a codevector generator for determining the characteristics of a bi-pulse codevector representative of the speech signal after said spectral information and said pitch information have been filtered out and for providing said characteristics for transmission, wherein the determination of said characteristics is made by only analyzing the correlation between each possible bi-pulse codevector and said backward filtered target vector, wherein said codevector generator examines said correlation to determine the largest positive and largest negative values.

Claim 10

Dependent Claim 36 words

The coder of claim 7, wherein said first filter has an impulse response and wherein said codevector generator comprises a truncator for truncating said impulse response and utilizing such truncated impulse response for determining said characteristics.

Claim 11

Dependent Claim 26 words

The coder of claim 7, wherein said codevector generator determines a set of largest positive values and a set of largest negative values for said correlation.

Claim 12

Dependent Claim 119 words

A speech coder for converting analog speech signals to digital speech signals for transmission, said speech coder comprising: a first filter for filtering out the spectral information from said speech signal and for providing said spectral information for transmission; a second filter for filtering out the pitch information from said speech signal and for providing said pitch information for transmission; and a codevector generator for determining the characteristics of a bi-pulse codevector representative of the speech signal after said spectral information and said pitch information have been filtered out and for providing said characteristics for transmission, said codevector generator comprising frequency-domain transform means for transforming codevector possibilities from being representative of pulse-like sound to being representative of noise-like sound.

Claim 13

Dependent Claim 119 words

A speech coder for converting analog speech signals to digital speech signals for transmission, said speech coder comprising: a first filter for filtering out the spectral information from said speech signal and for providing said spectral information for transmission; a second filter for filtering out the pitch information from said speech signal and for providing said pitch information for transmission; and a codevector generator for determining the characteristics of a bi-pulse codevector representative of the speech signal after said spectral information and said pitch information have been filtered out and for providing said characteristics for transmission, said codevector generator comprising frequency-domain transform means for transforming codevector possibilities from being representative of pulse-like sound to being representative of noise-like sound.

Claim 14

Dependent Claim 13 words

The coder of claim 10, wherein said transform means comprises a Hadamard transform.

Claim 15

Dependent Claim 22 words

The coder of claim 11, wherein said codevector generator further comprises a scrambler for modifying the sequency properties of transformed codevector possibilities.

Claim 16

Dependent Claim 57 words

The coder of claim 12, wherein said characteristics are capable of being determined by calculating the value of a fraction having a numerator and a denominator each being related to a number of codevector possibilities wherein said codevector generator only calculates said numerator and examines said numerators to determine which is the largest positive and largest negative.

Claim 17

Dependent Claim 221 words

A speech coder for converting analog speech signals to digital speech signals for transmission, said speech coder comprising: a first filter for filtering out the spectral information from said speech signal and for providing said spectral information for transmission; a second filter for filtering out the pitch information from said speech signal and for providing said pitch information for transmission; a first codevector generator for determining first characteristics of a bi-pulse codevector representative of the speech signal after said spectral information and said pitch information have been filtered out and for providing said first characteristics for transmission; a second codevector generator for determining second characteristics of a bi-pulse codevector representative of the speech signal after said spectral information and said pitch information have been filtered out and for providing said second characteristics for transmission, said second codevector generator comprising frequency-domain transform means for transforming codevector possibilities from being representative of pulse-like sound to being representative of noise-like sound; a third codevector generator for determining third characteristics of a single-pulse codevector representative of the speech signal after said spectral information and said pitch information have been filtered out and for providing said third characteristics for transmission; and a comparator for evaluating the characteristics determined by said first second and third codebook generators and choosing one of said first, second or third characteristics.

Claim 18

Dependent Claim 221 words

A speech coder for converting analog speech signals to digital speech signals for transmission, said speech coder comprising: a first filter for filtering out the spectral information from said speech signal and for providing said spectral information for transmission; a second filter for filtering out the pitch information from said speech signal and for providing said pitch information for transmission; a first codevector generator for determining first characteristics of a bi-pulse codevector representative of the speech signal after said spectral information and said pitch information have been filtered out and for providing said first characteristics for transmission; a second codevector generator for determining second characteristics of a bi-pulse codevector representative of the speech signal after said spectral information and said pitch information have been filtered out and for providing said second characteristics for transmission, said second codevector generator comprising frequency-domain transform means for transforming codevector possibilities from being representative of pulse-like sound to being representative of noise-like sound; a third codevector generator for determining third characteristics of a single-pulse codevector representative of the speech signal after said spectral information and said pitch information have been filtered out and for providing said third characteristics for transmission; and a comparator for evaluating the characteristics determined by said first second and third codebook generators and choosing one of said first, second or third characteristics.

Claim 19

Dependent Claim 23 words

The coder of claim 14, further comprising a weightor, for applying a weighting factor to one of said first, second and third characteristics.

Claim 20

Dependent Claim 15 words

The coder of claim 15 wherein said weighting factor is applied to said second characteristics.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1998-10-09	1999-04-10	1999-10-10	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2002-10-09	2003-04-10	2003-10-10	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2006-10-09	2007-04-10	2007-10-10	$7700.00	Window Closed / Lapsed

Adaptive speech coder having code excited linear prediction

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag