The bandwidth limitation of wideband audio degrades the subjective quality and the naturalness.In this paper

a bandwidth extension of audio signals from wideband to super-wideband was proposed by using a similarity correlation degree-based neural network.Firstly

the fine spectrum of wideband audio was converted to a multi-dimensional phase space.Then

a similarity correlation degree-based neural network was built up to reproduce the high-frequency fine spectrum.In addition

Gaussian mixture model was used to estimate the high-frequency spectral envelope.Finally

the bandwidth was extended to super-wideband by the proposed method in the ITU-T G.722.1 wideband codec.Evaluation results indicate that the proposed method is preferred over the reference methods and achieves a comparable subjective quality with the G.722.1C super-wideband codec.