Bandwidth extension of signal is defined as the deliberate process of expanding the frequency range (bandwidth) of a signal in which it contains an appreciable and useful content, and/or the frequency range in which its effects are such. Its significant advancement in recent years has led to the technology being adopted commercially in several areas including psychacoustic bass enhancement of small loudspeakers and the high frequency enhancement of perceptually coded audio. In the fields of communications, signal processing, and in electrical engineering more generally, a signal is any time-varying quantity. ... Bandwidth is a measure of frequency range, measured in hertz, of a function of a frequency variable. ... Psychoacoustics is the study of subjective human perception of sounds. ... Closeup of a loudspeaker driver Wall-mounted loudspeaker. ...

References

• http://www.dse.nl/~rmaarts/

• R.M. Aarts, Erik Larsen and O. Ouweltjes (2003), A unified approach to low- and high-frequency bandwidth extension, Convention Paper 5921 Presented at the AES 115th Convention 2003, Oct. 10--13, New York, USA