Vector quantization system and method of operation

(19)

(11)

EP 1 172 803 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	14.01.2004 Bulletin 2004/03

(43)	Date of publication A2:
	16.01.2002 Bulletin 2002/03

(21)	Application number: 01116530.5

(22)	Date of filing: 09.07.2001

(51)	International Patent Classification (IPC)⁷: G10L 19/06

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
	Designated Extension States:
	AL LT LV MK RO SI

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Priority:

13.07.2000 GB 0017145

(71)	Applicant: MOTOROLA, INC.
	Schaumburg, IL 60196 (US)

(72)	Inventors:
	Gibbs, Jonathan Alastair Southampton SO30 2XF (GB) Jasiuk, Mark Chicago, Illinois 60646 (US) Evans, Alun Downend, Bristol BS76 52 (GB) Smith, Aaron Streamwwod, Illinois 60107 (US)

(74)	Representative: Treleven, Colin et al
	Motorola European Intellectual Property Operations, Midpoint, Alencon Link Basingstoke, Hampshire RG21 7PL Basingstoke, Hampshire RG21 7PL (GB)

(54)	Vector quantization system and method of operation

(57) A method of providing robust quantization of speech spectral parameters tolerant to spectral balance and speaker variations, the method including the steps of, for each of a plurality of line spectral frequencies (LSFs) of a speech spectrum, quantizing (14) the displacement (12) of the LSF from an estimate (42) of its long-term mean, reconstructing (22,34) an estimate of the LSF from the quantized displacement and the long-term LSF mean estimate, and filtering (26,30,32) the reconstructed LSF estimate, thereby providing a subsequent long-term LSF mean estimate.

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