| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency-interpolating device or the like for restoring a highly-compressed audio signal keeping a high tone quality. SOLUTION: A PCM signal to which a frequency is interpolated is changed to the spectrum of the PCM signal by an analyzer 41. A spectrum-analyzing part 43 determines the band adjacent on the low frequency side to the deletion band, which does not contain the spectrum among the bands obtained by dividing the spectrum into several equal parts, or the past deletion band to be a band for interpolation. A frequency interpolation-processing part 44 presumes an envelope of the PCM signal; conducts scaling the spectrum having the same spectrum distribution as that in the band for the interpolation, which the spectrum analyzing part 43 determines, so that it can run along the function of the envelope, and adds the spectrum to the side having a higher frequency than the standard band. The past spectrum used for the scaling and the addition is read out from a spectrum-memorizing part 42. The synthesizer 45 generates the signal which gives a spectrum after the addition. |
