ADAPTIVE SOUND SOURCE VECTOR QUANTIZATION DEVICE AND ADAPTIVE SOUND SOURCE VECTOR QUANTIZATION METHOD
First Claim
1. An adaptive excitation vector quantization apparatus that searches for a pitch period in a fixed range for a first subframe of two subframes, the two frames being provided by dividing a frame, searches for a pitch period in a second subframe in a range in a vicinity of the pitch period determined in the first subframe, and using information about the searched pitch period as quantization data, the apparatus comprising:
- a first pitch period search section that searches for a pitch period in the first subframe by changing resolution with respect to a boundary of a predetermined threshold;
a calculation section that calculates a pitch period search range in the second subframe based on the pitch period determined in the first subframe and the predetermined threshold; and
a second pitch period search section that searches for a pitch period in the second subframe by changing resolution with respect to the boundary of the predetermined threshold in the pitch period search range.
3 Assignments
0 Petitions
Accused Products
Abstract
Provided is an adaptive sound source vector quantization device which can always perform a pitch cycle search with a resolution appropriate for any section of the pitch cycle search range of a second sub-frame when a pitch cycle search range of the second sub-frame changes in accordance with a pitch cycle of a first sub-frame. The device includes a first pitch cycle instruction unit (111), a search range calculation unit (112), and a second pitch cycle instruction unit (113). The first pitch cycle instruction unit (111) successively instructs pitch cycle search candidates in a predetermined search range having a search resolution which transits over a predetermined pitch cycle candidate for the first sub-frame. The search range calculation unit (112) calculates a predetermined range before and after the pitch cycle of the first sub-frame as the pitch cycle search range for the second sub-frame, if the predetermined range includes the predetermined pitch cycle search candidate. In the predetermined range, the search resolution transits over a boundary defined by the predetermined pitch cycle. The second pitch cycle instruction unit (113) successively instructs the pitch cycle search candidates in the search range for the second sub-frame.
284 Citations
2 Claims
-
1. An adaptive excitation vector quantization apparatus that searches for a pitch period in a fixed range for a first subframe of two subframes, the two frames being provided by dividing a frame, searches for a pitch period in a second subframe in a range in a vicinity of the pitch period determined in the first subframe, and using information about the searched pitch period as quantization data, the apparatus comprising:
-
a first pitch period search section that searches for a pitch period in the first subframe by changing resolution with respect to a boundary of a predetermined threshold; a calculation section that calculates a pitch period search range in the second subframe based on the pitch period determined in the first subframe and the predetermined threshold; and a second pitch period search section that searches for a pitch period in the second subframe by changing resolution with respect to the boundary of the predetermined threshold in the pitch period search range.
-
-
2. An adaptive excitation vector quantization method of searching for a pitch period in a fixed range for a first subframe of two subframes, the two frames being provided by dividing a frame, searching for a pitch period in a second subframe in a range in a vicinity of the pitch period determined in the first subframe and using information about the searched pitch period as quantization data, the method comprising the steps of:
-
searching for a pitch period in the first subframe by changing resolution with respect to a boundary of a predetermined threshold; calculating a pitch period search range in the second subframe based on the pitch period determined in the first subframe and the predetermined threshold; and searching for a pitch period in the second subframe by changing resolution with respect to the boundary of the predetermined threshold in the pitch period search range.
-
Specification