A Survey on High-Definition Voice Communication
The Narrow Band (NB) allows bandwidth of 300-3400Hz which is used in transmission of telephone system humiliates both the quality and clarity of speech. The absence of extension band spectral components causes narrow band speech signal wrapped and thin voiced. This is the main disadvantage of NB transmission. To improve the intelligibility of speech disgraced by narrow bandwidth, Researchers have tried to standardize the telephonic networks by introducing wide band (WB) of 50-7000Hz. The frequency range 50-7000Hz, and thus close up to so-called High Definition (HD) Voice calls. HD voice stands for coded wide band (WB) Speech this improves the speech quality and an improved user experience over conventional narrow band. WB speech (HD voice) transmission needs the transmission network and terminal devices at transmitter and receiver ends to be upgraded to the WB that turnout to be time taking process. For this Reason BWE techniques have been developed to overcome limitations of NB speech. This paper discusses various BWE techniques used for HD voice transmission with in Extension Band, application; challenges and limitations are also discussed.
Keywords - High-Definition, Narrow Band, Wide Band, Extension Band, Artificial Bandwidth Extension, Side information, Data Hiding.