For archiving damaged historical recordings, recoveries of missing portions are essentially important as well as noise reduction. Conventional counter-measures with functional interpolation are not effective when the missing interval is long. Inharmonic frequency analysis GHA is profitable for this purpose, because the recomposed signal with frequency components obtained by GHA exhibits very long period. Length of the period is given as an inverse number of least common multiple of rendered inharmonic frequency?fs periods. This feature is very advantageous for signal recovery, and the authors devised an extrapolation simply extending a re-synthesizing waveform obtained through GHA analysis/re-synthesis. The authors got satisfactory results a whole by applying interpolation combined with forward and backward extrapolations based upon abovementioned method. Results of recovery highly depend upon characters of signals (such as music) and the author did not find definite rules for setting GHA?fs analyzing conditions. Those are given through auditory examination this time.
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