Abstract: An audio signal interpolation device is presented, including an input unit for receiving an input audio signal, a phase splitting unit for splitting the input audio signal, a high range interpolation unit for interpolating a high range component into the signal, a phase combining unit for combining an in-phase component signal with a differential phase component, a high-pass filter for high-pass filtering the audio signal from by the phase combining unit, a delay unit for producing a delayed audio signal, and an addition processing unit for adding the delayed audio signal to the audio signal output from the high-pass filter.

Abstract: An audio signal interpolation method includes: a step of inputting an audio signal in which a higher range component has been cut off; a step of dividing the inputted audio signal into an in-phase component signal and a differential phase component signal; a step of combining the in-phase component signal and a differential phase component signal having a high range component interpolated; a step of performing a high-pass filtering on the combined audio signal and outputting the audio signal formed by a high range component; a step of delaying the inputted audio signal by a time corresponding to a phase delay caused by the interpolation; and a step of adding the delayed audio signal to the audio signal subjected to the high-pass filtering.