Method and apparatus for smoothing pitch-cycle waveforms

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(11)

EP 0 537 948 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	23.06.1993 Bulletin 1993/25

(43)	Date of publication A2:
	21.04.1993 Bulletin 1993/16

(21)	Application number: 92309167.2

(22)	Date of filing: 08.10.1992

(51)	International Patent Classification (IPC)⁵: G10L 9/14

(84)	Designated Contracting States:
	DE ES FR GB IT

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Priority:

18.10.1991 US 778560

(71)	Applicant: AT&T Corp.
	New York, NY 10013-2412 (US)

(72)	Inventor:
	Kleijn, Willem Bastiaan Basking Ridge, New Jersey 07920 (US)

(74)	Representative: Watts, Christopher Malcolm Kelway, Dr. et al
	AT&T (UK) Ltd. 5, Mornington Road Woodford Green Essex, IG8 0TU Woodford Green Essex, IG8 0TU (GB)

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References cited: :

(54)	Method and apparatus for smoothing pitch-cycle waveforms

(57) A method and apparatus for processing a reconstructed speech signal from an analysis-by-synthesis decoder are provided to improve the quality of reconstructed speech. By operation of the invention, one or more traces in a reconstructed speech signal are identified. Traces are sequences of like-features in the reconstructed speech signal. The like-features are identified by time-distance data received from the long term predictor of the decoder. The identified traces are smoothed by one of the known smoothing techniques. A smoothed version of the reconstructed speech signal is formed by combining one or more of the smoothed traces. The original reconstructed speech signal may be that provided by a long term predictor of the decoder. Values of the reconstructed speech signal and smoothed speech signal may be combined based on a measure of periodicity in speech.

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