Improving Sound Quality by Bandwidth Extension

In recent telecommunications system uses a limited audio signal bandwidth of 300 to 3400 Hz. In recent times it has been proposed that the mobile phone networks with increased audio signal bandwidth of 50Hz-7 KHz will increase the sound quality of the speech signal. In this paper, a method extending the conventional narrow frequency band speech signals into a wideband speech signals for improved sound quality is proposed. A possible way to achieve an extension is to use an improved speech coder/decoder (CODEC) such as the Adaptive Multi Rate – Wide Band (AMR-WB). However, using an AMR-WB CODEC requires that both telephones at the ends of the communication link support it. Moreover the Mobile phones communicating with wire-line phone can therefore not utilize the enhanced feature of new CODECS; to overcome this limitation the received speech signal can be modified. The modification is meant to artificially increase the bandwidth of the speech signal. The proposed speech bandwidth extension method is Feature Mapped Speech Bandwidth Extension. This method maps each speech feature of the narrow–band signal to a similar feature of the high-band and lowband, which generates the wide band speech signal Y(n). Index Term Speech analysis, speech enhancement, speech synthesis —————————— ——————————