Patent ID: 7177802
Filing Date: 2007-02-13
Classification: G10L

Abstract:
1. A pitch cycle search range setting apparatus comprising: a pitch cycle indicating section that, in pitch cycle search processing that searches for a pitch cycle included in a linear predictive residual on a subframe basis, sequentially indicates pitch cycle candidates within a preset pitch cycle search range with integral accuracy to an adaptive sound source vector generating section; an adaptive sound source vector generating section that extracts an adaptive sound source vector that has a pitch cycle indicated by said pitch cycle indicating section from an adaptive code book that stores past drive sound sources; and a last subframe integral pitch cycle storage section that stores the integral component of a pitch cycle finally selected in pitch cycle search processing of a previous subframe; wherein said pitch cycle search range setting apparatus sets as a pitch cycle search object, in processing subframe section pitch cycle search processing, both or one of an integral-accuracy pitch cycle candidate indicated by said pitch cycle indicating section and a fractional-accuracy pitch cycle search candidate that covers with fractional-accuracy a pitch cycle in the vicinity of an integral-accuracy pitch cycle read from said last subframe integral pitch cycle storage section.