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US5794199A Expired / Lapsed US ⏱️ 0.0 years remaining

Method and system for improved discontinuous speech transmission

Assignee: Texas Instruments Inc
•
Filing: 1996-01-29
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Granted: 1998-08-11
•
Expires: 2016-01-29
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Abstract

Abstract To overcome the problem of poor representation of the background noise, the present invention includes a noise parameter generator (40) which uses a weighted average of auto-correlation values of the input signal generated during the noise-analysis phase. The weighting function gives less weight to the auto-correlations during the first few frames (as they may contain speech) and more weight to frames towards the end of this phase. Also included, to overcome the bursty nature of comfort noise, is a comfort noise generator (50) which gradually changes the nature of the signal from speech to pseudo-random noise after the speech-burst. The comfort noise generator (50) of the present invention excites the auto-regressive filter corresponding to the noise model with a weighted combination of the past excitation and pseudo-random noise.

Inventors

  • 👤 Ajit V. Rao
  • 👤 Wilfrid P. LeBlanc

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 20:54
CPC Classifications
G; G10; G10L; G10L19/00; G10L19/012

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 129 words
A method of generating comfort noise to interleave between bursts of speech in a speech synthesizer, comprising the steps of: providing an 8th order auto-regressive filter ##EQU4## where n=1, 2, . . . , 40; i=(k+1), . . . , N; and where j=1, 2, . . . , 40; feeding a first excitation signal, e i ,j (n), to the 8th order auto-regressive filter with coefficients a 0!=1.0, a 1!, . . . , a 8! to generate a synthetic speech component, s(i, j) n! in each noisy subframe (i, j); and generating a second excitation signal which includes both a pseudo-random noise component and a component which depends upon past excitations, wherein said component which depends upon past excitations is the synthetic speech component, s(i, j) n!.
Claim 2
Independent Claim 129 words
A method of generating comfort noise to interleave between bursts of speech in a speech synthesizer, comprising the steps of: providing an 8th order auto-regressive filter ##EQU4## where n=1, 2, . . . , 40; i=(k+1), . . . , N; and where j=1, 2, . . . , 40; feeding a first excitation signal, e i ,j (n), to the 8th order auto-regressive filter with coefficients a 0!=1.0, a 1!, . . . , a 8! to generate a synthetic speech component, s(i, j) n! in each noisy subframe (i, j); and generating a second excitation signal which includes both a pseudo-random noise component and a component which depends upon past excitations, wherein said component which depends upon past excitations is the synthetic speech component, s(i, j) n!.
Claim 3
Dependent Claim 14 words
The method of claim 1 wherein said pseudo-random noise component is white Gaussian noise.
Claim 4
Dependent Claim 19 words
The method of claim 1 wherein said synthetic speech component is a randomly delayed segment of an adaptive codebook.
Claim 5
Dependent Claim 23 words
The method of claim 1 wherein a weighting is given to said synthetic speech component and wherein said weighting is reduced over time.
Claim 6
Dependent Claim 50 words
The method of claim 1 wherein each of said first and second excitation signals, e i ,j (n), is a weighted sum e.sub.i,j (n)=(1-f.sub.i)N(0,σ.sup.2)+f.sub.i d(n-1.sub.(i,j)) where 1.sub.(i,j) is a uniformly distributed random number whose range depends on the memory of said adaptive codebook and where f, is a weighting factor.
Claim 7
Dependent Claim 16 words
The method of claim 5 wherein said weighting factor, f, is f i =0.95 i .

References Cited (Backward Citations)

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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2001-08-10 2002-02-09 2002-08-11 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2005-08-10 2006-02-09 2006-08-11 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2009-08-10 2010-02-09 2010-08-11 $7700.00 Window Closed / Lapsed

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