2000-338998 is referenced by 17 patents.

PROBLEM TO BE SOLVED: To encode an input voice containing a tone component much in high area with high efficiency by dividing the frequency area coefficient of an input signal sample to generate a coefficient small piece group, classifying the coefficient small pieces to a plurality of groups followed by flattening, and encoding them.SOLUTION: An input signal is converted to the coefficient of frequency area, and a series of coefficients are bundled every band of about 100 Hz width to form coefficient small pieces, and the respective coefficient small pieces are classified to a high level group and low level group according to the intensities. For example, when the magnitude of the coefficient of frequency area is fluctuated as in a modified discrete conversion (MDCT) coefficient, the adjacent coefficients are bundled to form coefficient small pieces, and the coefficient small pieces are classified to a small coefficient group G0 and a large coefficient group G1. After the group G1 with high intensity and the group G0 with low intensity are independently flattened, the two groups G0 and G1 are collected to one followed by vector quantization.

Title
Audio signal encoding method and decoding method, device therefor, and program recording medium
Application Number
2000-078370
Publication Number
2000-338998
Application Date
March 21, 2000
Publication Date
December 8, 2000
Inventor
Mori Takeshi
Chikira Kazuaki
Jin Akio
Moriya Takehiro
Iwagami Naoki
Assignee
Nippon Telegr &Amp Teleph Corp &Lt Ntt&Gt
IPC
H04B 14/04
H03M 07/30
G10L 19/00
G10L 11/00
G10L 19/02