Artificial Bandwidth Extension Method of telephony Speech in Mobile Terminal: A Review
The restricted audio quality of today's telephone networks is mainly due to the Narrow Band (NB) limitation to the frequency range from about 300 Hz to 3.4 KHz. Meanwhile, codecs for Wide Band (WB) telephony (50Hz to 7 kHz) exist with significantly improved speech intelligibility and naturalness. However, the broad introduction of wideband speech coding will require strong efforts of both network operator and customers because many elements of the networks have to be modified. The intermediate solution to overcome this narrowband limitation can be achieved by applying Artificial Bandwidth Extension (ABE) in the receiving terminal.