Patent ID: 7149682

Claim:
An apparatus for converting an input voice signal into an output voice signal by modifying a spectral shape, the apparatus comprising: an input device that provides the input voice signal containing wave components; a separating device that separates sinusoidal ones of the wave components from the input voice signal such that each sinusoidal wave component is identified by a pair of a frequency and an amplitude; a computing device that computes a spectral shape of the input voice signal based on a set of the separated sinusoidal wave components such that the spectral shape represents an envelope having a series of break points corresponding to the pairs of the frequencies and the amplitudes of the sinusoidal wave components; a modifying device that modifies the spectral shape to form a new spectral shape representing a modified envelope having a series of new break points by shifting the envelope along an axis of the frequency on a coordinates system of the frequency and the amplitude, the modifying device using a function defining a relation between a modification degree and a pitch, and determining the modification degree of a frequency or an amplitude of each break point of the new spectral shape according to a specific pitch of the output voice signal by using the function; a generating device that determines a series of frequencies according to the specific pitch of the output voice signal, and that selects a series of points which are positioned along the modified envelope of the new spectral shape in correspondence to the series of the determined frequencies, but which are different from the series of the new break points of the modified envelope, and that generates a set of new sinusoidal wave components each identified by each pair of a frequency and an amplitude, which corresponds to each of the series of the selected points; and an output device that produces the output voice signal based on the set of the new sinusoidal wave components.