Title:
VOICE SIGNAL CODING METHOD, DECODING METHOD
Document Type and Number:
Japanese Patent JP3490325
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To reproduce a high naturalness and high quality voice with an over- poweringly low bit rate while suppressing quality deterioration by specifying a frequency band of an input voice to the band of about 5 kHz and balancing an information amount incorporated in the voice with coding efficiency.
SOLUTION: For instance, when a coding system of frame length 10 ms, a bit rate 7.8 kbits/s is designed, a voice signal is low-pass filter processed to be band limited to 5 kHz or below. Analytic frame length is 110 samples, and this is equivalent to nearly 10 ms. The number of sub-frames is made 2, and look-ahead is made 1 sub-frame 5 sm. A linear predictive parameter is coded by two stage vector quantization using moving average prediction, and 1 bit is used to moving average predictive mode switching, and 7 bits are used to a first stage, and second stage is divided to a low-order and a high-order, and 5 bits are used to respective orders. When 11.025 kHz sampling is used, in an adaptive code book, 8 bits are allocated to an adaptive code book index, and 5 bits are used for a second sub-frame.
Inventors:
Noboru Harada
Naka Omuro
Naka Omuro
Application Number:
JP3811299A
Publication Date:
January 26, 2004
Filing Date:
February 17, 1999
Export Citation:
Assignee:
Nippon Telegraph and Telephone Corporation
International Classes:
G10L19/00; G10L19/04; G10L19/06; G10L19/09; G10L19/107; G10L19/24; H03M7/30; H04B14/04; (IPC1-7): G10L19/00; G10L19/04; H03M7/30; H04B14/04
Domestic Patent References:
| JP736495A | ||||
| JP6153119A | ||||
| JP5199071A | ||||
| JP6124100A |
Attorney, Agent or Firm:
Kusano Taku (1 person outside)