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Methods and arrangements in a telecommunications network

A voice signal and post-filter technology, applied in voice analysis, instruments, etc., can solve problems such as inaudible

Active Publication Date: 2012-05-30
TELEFON AB LM ERICSSON (PUBL)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

State-of-the-art post-filter algorithms 105 shape the quantization noise, making it less audible

Method used

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  • Methods and arrangements in a telecommunications network
  • Methods and arrangements in a telecommunications network
  • Methods and arrangements in a telecommunications network

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Embodiment Construction

[0021] The basic concept of the invention is to modify the existing post-filter such that it adapts to the spectral dynamics of the decoded speech signal. (It should be noted that even though the term speech is used in this paper, the specification refers to any audio signal.) The spectral dynamics imply a measure of the stationarity of the signal, defined as the Euclidean difference between the spectral densities of two adjacent speech segments Reid distance. If the Euclidean distance between two speech segments is high, the attenuation should be reduced compared to the case when the Euclidean distance is low.

[0022] The modified post-filter according to the invention makes it possible to suppress more noise at low dynamics and less at high dynamics, e.g. during formant transitions and vowel onsets noise.

[0023] This accounts for the fact that the average level of quantization noise may not vary rapidly over time, but in some parts of the signal the noise will be more a...

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Abstract

The present invention relates to a postfilter and a postfilter control to be associated with a postfilter for improving perceived quality of speech reconstructed at a speech decoder. The postfilter control comprises means for measuring stationarity of a speech signal reconstructed at a decoder, means for determining a coefficient to a postfilter control parameter based on the measured stationarity, and means for transmitting the determined coefficient to a postfilter, such that the postfilter can process the reconstructed speech signal by applying the determined coefficient to the postfilter control parameter to obtain an enhanced speech signal.

Description

technical field [0001] The present invention relates to post filter algorithms used in speech and audio coding. In particular, the present invention relates to methods and apparatus for providing improved post filters. Background technique [0002] In a communication network for transmitting speech or audio, the original speech 100 or audio is encoded by an encoder 101 at the transmitter, and the encoded bit stream 102 is transmitted to e.g. image 3 Receiver shown. At the receiver, the encoded bitstream 102 is decoded by a decoder 103 which reconstructs the original speech and audio signal into a reconstructed speech (or audio) 104 signal. Speech and audio coding introduces quantization noise, which impairs the quality of reconstructed speech. Therefore, a post filter algorithm 105 is introduced. A state-of-the-art post-filter algorithm 105 shapes the quantization noise, making it less audible. Thus, the existing post-filter improves the perceptual quality of the speech...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G10L19/14
CPCG10L21/013G10L21/003G10L21/0205G10L21/02G10L19/26G10L21/0364
Inventor V·格兰查罗夫
Owner TELEFON AB LM ERICSSON (PUBL)