Pitch lag estimation system

(19)

(11)

EP 0 713 208 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	10.12.1997 Bulletin 1997/50

(43)	Date of publication A2:
	22.05.1996 Bulletin 1996/21

(21)	Application number: 95118142.9

(22)	Date of filing: 17.11.1995

(51)	International Patent Classification (IPC)⁶: G10L 3/00

(84)	Designated Contracting States:
	DE FR GB

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Priority:

21.11.1994 US 342494

(71)	Applicant: ROCKWELL INTERNATIONAL CORPORATION
	Seal Beach, California 90740-8250 (US)

(72)	Inventors:
	Su, Huan-Yu Irvine, California 92714 (US) Li, Tom Hong Middletown, New Jersey 07748 (US)

(74)	Representative: Wagner, Karl H. et al
	WAGNER & GEYER Patentanwälte Gewürzmühlstrasse 5 D-80538 München D-80538 München (DE)

(54)	Pitch lag estimation system

(57) A pitch estimation device and method utilizing a multi-resolution approach to estimate speech pitch lag. The system includes sampling the speech 602 and applying, alternately, a discrete Fourier transform 606 and squaring the result 608. A DFT on the squared amplitude is then performed 610 to transform the speech samples into another domain. An initial pitch lag can then be found with lower resolution. After getting the low-resolution pitch lag estimate, a refined algorithm is applied 618 to get a higher-resolution pitch lag. The refined algorithm is based on minimizing the prediction error in the time domain. The refined pitch lag then can be used directly in the speech coding.

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