The bandwidth limitation in wideband audio communication systems degrades the subjective quality and naturalness of the reproduced signals.In this paper

a wideband to super-wideband audio bandwidth extension method was proposed by using echo state network.The echo state network is adopted to model the mapping function between the low-and high-frequency spectral coefficients of audio signals

and the temporal evolution of audio features is represented by continuously state updating on the basis of the recursive structure in the network

for effectively estimating the high-frequency spectral envelope.By combining the high-frequency fine spectrum extended by spectral translation

the proposed method can effectively extend the bandwidth of wideband audio to super-wideband.Evaluation results show that the proposed method upgrades the auditory quality of wideband audio

and gains better extension performance than the Gaussian mixture model-based bandwidth extension method in terms of both static and dynamic distortions for most test data.