MARK J JOHNSON
Accountancy in Cambridge, MA

5323486, Jun 21, 1994

May 14, 1992

7/856221

Tomohiko Taniguchi - Kawasaki, JP
Mark Johnson - Cambridge MA
Yasuji Ohta - Kawasaki, JP
Hideaki Kurihara - Kawasaki, JP
Yoshinori Tanaka - Kawasaki, JP
Yoshihiro Sakai - Kawasaki, JP

Fujitsu Limited - Kawasaki

G10L 900

395 231

A speech coding system is provided where input speech is coded by finding via an evaluation computation a code vector giving a minimum error between reproduced signals obtained by linear prediction analysis filter processing, simulating speech path characteristics, on code vectors successively read out from a noise codebook storing a plurality of noise trains as code vectors and an input speech signal and by using a code specifying the code vector. In the speech coding system, the noise codebook includes a delta vector codebook which stores an initial vector and a plurality of delta vectors having difference vectors between adjoining code vectors. In addition, provision is made in the computing unit for the evaluation computation of a cyclic adding unit for cumulatively adding the delta vectors to virtually reproduce the code vectors.

5199076, Mar 30, 1993

Sep 18, 1991

7/761048

Tomohiko Taniguchi - Kawasaki, JP
Mark A. Johnson - Cambridge MA
Hideaki Kurihara - Kawasaki, JP
Yoshinori Tanaka - Kawasaki, JP
Yasuji Ohta - Kawasaki, JP

Fujitsu Limited

G10L 500

381 36

A CELP type speech coding system is provided with an arithmetic processing unit which transforms a perceptual weighted input speech signal vector AX to a vector. sup. t AAX, a sparse adaptive codebook which stores a plurality of pitch prediction residual vectors P sparsed by a sparse unit, and a multiplying unit which multiplies the successively read out vectors P and the output. sup. t AAX from the arithmetic processing unit. In addition, the CELP type speech coding system includes a filter operation unit which performs a filter operation on the vectors P, and an evaluation unit which finds the optimum vector P based on the output from the filter operation unit, so as to enable reduction of the amount of arithmetic operations.

5799131, Aug 25, 1998

Mar 3, 1997

8/811451

Tomohiko Taniguchi - Yokohama, JP
Mark Johnson - Cambridge MA

Fujitsu Limited - Kawasaki

G10L 916

395 213

A speech coding and decoding system, where the system is operated under a known code-excited linear prediction (CELP) coding method. The CELP coding is achieved by selecting an optimum pitch prediction residual vector P from an adaptive codebook and the corresponding first gain, and at the same time, selecting an optimum code vector C from a white-noise stochastic codebook and the corresponding second gain. The system of the present invention is implemented by a weighted orthogonalization transforming unit introduced therein. The perceptually weighted code vector AC is not used as in the prior art. Rather, the weighted orthogonalization transformation unit transforms the code vector into a perceptually weighted reproduced code vector AC' being made orthogonal to the optimum perceptually weighted pitch prediction vector AP.

5245662, Sep 14, 1993

Jun 18, 1991

7/716882

Tomohiko Taniguchi - Yokohama, JP
Mark Johnson - Cambridge MA

Fujitsu Limited - Kawasaki

G10L 500

381 36

A speech coding system operated under a known code-excited linear prediction (CELP) coding method. The CELP coding is achieved by selecting an optimum pitch vector P from an adaptive codebook and the corresponding first gain and, at the same time, selecting an optimum code vector from a sparse-stochastic codebook and the corresponding second gain. Special code vectors are loaded in the sparse-stochastic codebook, which code vectors are hexagonal lattice code vectors each consisting of a zero vector with one sample set to +1 and another sample set to -1.