Vector quantizing device for LPC parameters

A parameter vector and vector quantization technology, applied in code conversion, electrical components, speech analysis, etc., can solve problems such as unusable, memory capacity growth, etc.

Inactive Publication Date: 2004-04-07
PANASONIC CORP +1
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the above solutions lead to a drastic increase in memory capacity for storing alternative code vectors
Furthermore, when considering that vector quantizers using "predictive vector quantization technology" or "multi-stage vector quantization technology" are frequently used in low bit rate speech coding systems, it is necessary to store in the codebook in advance the LPC cepstrum without interaction Transformative vectors (e.g., prediction residual vectors or quantization error vectors), and therefore cannot use the above-mentioned workarounds

Method used

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  • Vector quantizing device for LPC parameters
  • Vector quantizing device for LPC parameters
  • Vector quantizing device for LPC parameters

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Embodiment 1

[0044] The LPC vector quantization apparatus according to the present invention will be explained using FIG. 3 . Fig. 3 is a block diagram showing the configuration of an LPC vector quantization apparatus according to Embodiment 1 of the present invention.

[0045] This vector quantization device is equipped with following parts: LSF code book 101, is used for storing LSF code vector entry; Distortion calculation part 102, is used for calculating the distance between the LSF code vector entry in LSF code book 101 and the target LSF vector Distortion; LPC code pre-selection part 103, for preliminarily selecting the LPC code of the small number of preset based on the distortion calculated by distortion calculation part 102; LSF / LPC conversion part 104 and 106, for converting LSF vector to LPC coefficients; LPC coefficient / LPC cepstrum conversion sections 105 and 107 for converting LPC coefficients to LPC cepstrum; and LPC code final search section 108 for final selection based o...

Embodiment 2

[0080] This embodiment will explain the configuration of the vector quantization device and its processing procedure when the technique according to the present invention is applied to the LPC parameter vector quantization device by using the predictive vector quantization technique, the multi-stage vector quantization technique, and the separation vector quantization technique together and effect / action.

[0081] The configuration of the vector quantization means strongly depends on the bit rate of the overall speech encoder / decoder and the number of bits allocated to the LPC vector quantization means. Here, for simplicity of explanation, a vector quantization device assigned 21-bit bit information per 20 ms time interval processing frame will be explained below as a specific example.

[0082] Also, more specifically, it is assumed that the vector quantization apparatus used in this explanation uses the third-order MA (Movement Average) prediction technique and uses 4 sets of...

Embodiment 3

[0153] 6 is a block diagram showing the configuration of a vector quantization device according to Embodiment 3. Incidentally, components of the vector quantization device shown in FIG. 6 that are the same as those in FIG. 5 explained in Embodiment 2 are assigned the same reference numerals as those in FIG. 5 and will be omitted its detailed explanation.

[0154] The vector quantization device shown in FIG. 6 employs a configuration having a low-frequency scalefactor codebook 350 and a high-frequency scalefactor codebook 360 added to the vector quantization device in FIG. 5 . Incidentally, in FIG. 6, components 301 to 306 and 316 to 323 are omitted to make the diagram easier to see.

[0155] Incidentally, as in the case of Embodiment 2, the configuration of the vector quantization means strongly depends on the bit rate of the entire speech encoder / decoder and the number of bits allocated to the LPC parameter vector quantization means. Here, for simplicity of explanation, it ...

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Abstract

The present invention carries out pre-selection on many LPC codevectors stored in an LSF codebook 101 using a weighted Euclidean distortion as a measure and carries out a full-code selection on the LPC codevectors left after the pre-selection using an amount of distortion in a spectral space as a measure. This makes it possible to improve the quantization performance of the LPC parameter vector quantizer and improve the quality of synthesized speech of the speech coder / decoder.

Description

technical field [0001] The present invention relates to an LPC vector quantization device applied to a speech encoder / decoder for enhancing the transmission efficiency of speech signals in the field of packet communication systems represented by Internet communication and mobile communication systems and the like. Background technique [0002] When a voice signal is transmitted in a packet communication system represented by an Internet communication or a mobile communication system, compression / encoding techniques are often used to enhance the transmission efficiency of the voice signal. Many speech encoding systems have been developed at present, and many low-bit-rate speech encoding systems developed in recent years separate speech signals into spectrum envelope information and sound source information and compress / encode the separated pieces of information. For example, in Document 1 (M.R. Schroeder, B.S. Atal, "Code Excited Linear Prediction: High Quality Speech at Low ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10L19/06G10L19/038G10L19/07H03M7/30
CPCG10L19/07H03M7/3082G10L2019/0005G10L2019/0014G10L19/06G10L19/038
Inventor 安永和敏森井利幸江原宏幸间野一则日和崎佑介
Owner PANASONIC CORP
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