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To decrease the spectral distortion of highband envelope,the function of spectral distortion and mutual information between feature vector and highband envelope was studied, and an extended Gaussian Mixture Model(GMM) bandwidth extension algorithm was proposed based on the research.The feature parameters which have larger mutual information with highband envelope were selected to constitute the feature vector,and the GMM was adopted to compute the joint probability density of the feature vector and highband envelope.Then the highband envelope was estimated via the posterior probabilities computed from the model parameters estimated by Expectation-Maximization(EM) algorithm.The experimental results show that the spectral distortion is lower than the algorithm,such as the traditional algorithm based on GMM,by 0.3 dB and the number of frames with spectral distortion over 10 dB sharply reduced over 50%.
To decrease the spectral distortion of high band envelope, the function of spectral distortion and mutual information between feature vector and highband envelope was studied, and an extended Gaussian Mixture Model (GMM) bandwidth extension algorithm was proposed based on the research. The feature parameters which have larger mutual information with highband envelope were selected to constitute the feature vector, and the GMM was adopted to compute the joint probability density of the feature vector and highband envelope.Then the highband envelope was estimated via the posterior probabilities computed from the model parameters estimated by Expectation-Maximization (EM) algorithm. The experimental results show that the spectral distortion is lower than the algorithm, such as the traditional algorithm based on GMM, by 0.3 dB and the number of frames with spectral distortion over 10 dB sharply reduced over 50% .