Title:
ボコーダの動作方法
Document Type and Number:
Japanese Patent JP4690356
Kind Code:
B2
Abstract:
A fixed codebook response is able to better characterize an input signal of a vocoder because the entries of the fixed codebook are tailored to the input signal being processed. A uniformly distributed random noise signal is stored in a transmitting vocoder. During encoding by the transmitting vocoder, the noise signal is shaped by a weighing filter and a pitch sharpening filter, which are condition controlled by the linear predictive coding, pitch and pitch gain characteristics of the input signal being encoded. The shaped noise signal is passed though a thresholding filter to arrive at a pulse sequence having a given sparcity. The fixed codebook response is chosen as that portion of the pulse sequence which best matches a residual signal of the input signal. The indexed location of that portion along the pulse sequence is designated as the fixed codebook bits which are included within the bit frame. The identical random noise signal is stored in a receiving vocoder. The linear predictive coding, pitch, and pitch gain characteristics are part of the bit frame, and are again used to produce an identical pulse sequence. The fixed codebook bits of the bit frame are used to index the pulse sequence to the best matching portion, and hence the fixed codebook response for the bit frame.
Inventors:
Engine Yeltsin
Michael Charles Lekkion
Michael Charles Lekkion
Application Number:
JP2007074674A
Publication Date:
June 01, 2011
Filing Date:
March 22, 2007
Export Citation:
Assignee:
Alcatel-Lucent USA Inc.
International Classes:
G10L19/00; G10L19/038; G10L19/107; G10L19/12; H04B14/04
Domestic Patent References:
| JP6130994A | ||||
| JP5158497A | ||||
| JP511799A | ||||
| JP6214599A | ||||
| JP8146998A |
Foreign References:
| WO1999012156A1 |
Attorney, Agent or Firm:
Okabe
Masao Okabe
Nobuaki Kato
Shinichi Usui
Takao Ochi
Asahi Shinmitsu
Masao Okabe
Nobuaki Kato
Shinichi Usui
Takao Ochi
Asahi Shinmitsu