Patent ID: 7505899
Filing Date: 2009-03-17
Classification: G10L

Abstract:
1. A speech code sequence conversion apparatus comprising: a decoding circuit for a first code sequence, which separates and decodes the first code sequence into components including i) a quantization linear prediction (LP) coefficient, ii) a pitch period, and iii) a residual error component signal, and speech synthesizes the components to produce a decoded signal; and a coding circuit for a second code sequence, which i) cuts the decoded signal by a frame length of a second code sequence including the pitch period, ii) further divides the frame length into sub-frame lengths of the second code sequence, iii) vector-quantizes the LP coefficient of the first code sequence to produce a quantized LP coefficient, iv) codes a pitch component into an optimum pitch, and v) codes and synthesizes calculated and obtained residual error components, to output a coded signal, wherein the coding circuit includes pitch component coding means for i) receiving the pitch period of the first code sequence from a pitch component decoding circuit of the decoding circuit, and for ii) producing the pitch period of the first code sequence and a plurality of pitch period candidates in a vicinity of the pitch period of the first code sequence, for each sub-frame length that is a time unit to code a pitch period of the second code sequence, as the pitch period candidates of the second code sequence.