A method includes receiving an audio signal and identifying one or more steady-state segments of the audio signal. The method also includes identifying at least one portion of the one or more segments that contains a specified frequency. Further, the method includes generating a wavetable using the at least one identified portion of the one or more segments. In addition, the method could include synthesizing an output audio signal using the wavetable. The output audio signal could represent a ringtone in a mobile telephone.