SOUND QUALITY IMPROVEMENT APPARATUS AND METHOD

PROBLEM TO BE SOLVED: To improve the articulation rate of a sound source by restoring a signal of a high frequency band from a signal of a low frequency band.SOLUTION: A sound quality improvement apparatus 501 includes an envelope curve detection unit 502 for detecting a frequency envelope curve of an input signal by using energy of each frequency band with respect to the low frequency band of the input signal, a signal restoration unit 503 for restoring the input signal of the high frequency band by performing frequency folding at a frequency section unit by the frequency envelope curve, and an envelope curve adjustment unit 504 for adjusting an envelope curve corresponding to the restored high frequency band by considering the tilt of an envelope curve corresponding to the low frequency band of the input signal.