Patent ID: 8000976

Claim:
A speech band extension device comprising: band-extended audio generation means which generates a band-extended audio signal from an original audio signal, the band-extended audio signal including a component lying within a frequency band that is not included in a frequency band of the original audio signal; timing shift detection means which detects a timing shift between the original audio signal and the band-extended audio signal; adjustment means which adjusts one of timing of the band-extended audio signal and timing of both the band-extended audio signal and the original audio signal, in accordance with the detected timing shift; and combination means which combines the original audio signal and the band-extended audio signal after the adjusting of the timing; wherein the adjustment means, which treats each audio frame of a predetermined period of time as a processing unit, generates a delayed band-extended audio signal by inserting a delay time corresponding to the detected timing shift, calculates a waveform period at a latest edge portion of the delayed band-extension audio signal, replicates a signal waveform, corresponding to a predetermined number of waveform periods from the latest edge portion of the delayed band-extended audio signal to an oldest portion of the delayed band-extended audio signal, and uses the replicated signal waveform as an interpolation signal at a position shifted toward the latest edge portion, and combines a portion of the interpolation signal, corresponding to a shortage of the signal waveform occurring in the latest edge portion of the audio frame of the delayed band-extended audio signal, with the delayed band-extended audio signal, thereby generating the band extended audio signal after the adjusting of timing.