Shaped fixed code book searching used for code exciting linear predicting speech encode

Application Number: 00107074
Application Date: 2000.04.27
Publication Number: 1271925
Publication Date: 2000.11.01
Priority Information: 1999/4/28 US 09/300,314
International: G10L19/00
Applicant(s) Name: Lucent Technologies Inc.
Address:
Inventor(s) Name: Y. Aisen;M. C. Ridgan
Patent Agency Code: 11038
Patent Agent: jiang shixun
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.