Topic
Code-excited linear prediction
About: Code-excited linear prediction is a research topic. Over the lifetime, 2025 publications have been published within this topic receiving 28633 citations. The topic is also known as: CELP.
Papers published on a yearly basis
Papers
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TL;DR: Significant noise reduction has been observed in typical rooms at a source‐to‐array distance of 1 m and the quality of the desired speech coded in the presence of acoustic interference is enhanced by the array processing.
Abstract: Arrays of simple, unmatched microphones have been applied to two speech processing problems. The first application is noise reduction via robust constrained beamforming. Significant noise reduction has been observed (10 dB) in typical rooms at a source‐to‐array distance of 1 m. The noise reduction achievable is proportional to the direct‐to‐reverberant energy ratio of the interfering sound energy (from a single location in the room). The robust adaptive processing avoids the cancellation of the desired signal in all cases examined. The second application is speech coding. A standard code‐excited‐linear‐prediction (CELP) codec is used in conjunction with the microphone array and noisy speech inputs. The quality of the desired speech coded in the presence of acoustic interference is enhanced by the array processing. Signal‐to‐noise ratios, intelligibility averaged gains, other spectral measures, and spectral envelope measures have been compared to assess the relative quality of the spatially filtered and co...
1 citations
01 Nov 2017
TL;DR: In the experiments, the aural effect of encoded speech has been improved by the proposed method of power spectrum estimation and filtering analysis.
Abstract: Efforts to eliminate the noise of CELP coding method have been made in order to get better aural effect. The emphasis of eliminating the noise is usually attached on CELP coders. However, this paper pays more attention to encoded speech by using power spectrum estimation and filtering analysis. In the experiments, the aural effect of encoded speech has been improved by the proposed method.
1 citations
01 Oct 2017
TL;DR: A procedure for designing a speech production model that takes the samples of speech as input and generates the essential parameters from which the decoded speech can be obtained close to the original speech is described.
Abstract: In the speech signal transmission, there is lot of difference between the bit rate requirement and information rate Many codec were designed for speech coding to decrease the bandwidth requirements This paper aims to provide a technical aspect for designing the encoder for 590 kbps Narrow-band AMR codec using MATLAB as simulation tool This paper describes a procedure for designing a speech production model that takes the samples of speech as input and generates the essential parameters from which the decoded speech can be obtained close to the original speech Beyond AMR, additional techniques supporting codec like AMR-WB and Enhanced Voice Service are working for 3G and 4G services respectively
1 citations
Patent•
16 Mar 2006
TL;DR: In this article, an adaptive code book is used to store the past drive sound source used in a synthetic filter and generates the sound source vector of one subframe component from the stored sound source according to the adaptive code books lag corresponding to an index F1 instructed from a distortion minimization section 107.
Abstract: PROBLEM TO BE SOLVED: To provide a voice-coder etc., capable of improving encoding efficiency while suppressing the occurrence of delay in subjecting a stereo voice signal to CELP encoding. SOLUTION: An adaptive code book 101 stores the past drive sound source used in a synthetic filter 112, and generates the sound source vector of one subframe component from the stored drive sound source according to the adaptive code book lag corresponding to an index F1 instructed from a distortion minimization section 107. A fixed code book 103 previously stores a plurality of the sound source vectors of a prescribed shape and outputs the sound source vector corresponding to the index F1 instructed from the distortion minimization section 107 as the fixed code book vector to a multiplier 104. An adder 105 adds the adaptive code book vector outputted from the multiplier 102 and the fixed code book vector output from the multiplier 104, and outputs the sound source vector after the addition to a first channel encoding section 110-1 and a second channel encoding section 110-2 as a drive sound source. COPYRIGHT: (C)2006,JPO&NCIPI
1 citations
Patent•
27 Mar 2009
TL;DR: In this paper, the authors proposed a hybrid coder to reduce interference in the decoded signal, which is formed from the first decoded signals constituent (S_CELP) and the second decoding signal constituent(S_TDAC), containing the following stages: obtaining the first enveloping characteristics (ENV_CelP) of energy of the second encoder, and in the preferred manner, multiplication of second decoder signal constituent with the amplification coefficient.
Abstract: FIELD: physics, acoustics ^ SUBSTANCE: invention relates to the method of decoding signals, which are coded using a hybrid coder Essence of the invention lies in the method of reducing interference (S-OUT) in the decoded signal, which is formed from the first decoded signal constituent (S_CELP) and the second decoded signal constituent (S_TDAC), containing the following stages: obtaining the first enveloping characteristics (ENV_CELP) of energy and the second enveloping characteristics (EN_TDAC) of energy of the first decoded signal constituent (S_CELP) and the second decoded signal constituent (S_TDAC), forming the characteristic number (R) depending on the comparison of the first and second enveloping characteristics (ENV_CELP, ENV_TDAC) of energy; output of the amplification coefficient (G) depending on the characteristic number (R); in the preferred manner, multiplication of second decoded signal constituent with the amplification coefficient ^ EFFECT: providing a reduction of interference noises anticipating an echo and the following echo for signals, coding using a hybrid coder without requiring additional information ^ 13 cl, 4 dwg
1 citations