Granted Patent B2

US 12,694,883 · App. 18/383,594 · Granted Jul 28, 2026

Inventors: Takehiro Moriya (Atsugi, JP); Yutaka Kamamoto (Atsugi, JP); Noboru Harada (Atsugi, JP)

Assignee: NTT, Inc.

G10L19/06G10L19/12G10L19/02G10L19/0212

Abstract

Claims (12)

1 . A periodic-combined-envelope-sequence generation device comprising:

processing circuitry configured to:

execute a spectral-envelope-sequence calculating processing which takes, as an input audio signal, a time-domain audio digital signal in each frame which is a predetermined time segment, and calculates a spectral envelope sequence of the input audio signal on the basis of time-domain linear prediction of the input audio signal; and

execute a periodic-combined-envelope generating processing which transforms the spectral envelope sequence to a periodic combined envelope sequence on the basis of a periodic component of the input audio signal in the frequency domain;

wherein the periodic-combined-envelope generating part modifies the periodic combined envelope sequence based on a value that determines a mixture ratio between the spectral envelope sequence and the periodic component; and

the value that determines the mixture ratio is chosen such that the shape of the periodic combined envelope sequence and the shape of absolute values of a coefficient string which is transformed from the input audio signal in the frequency domain becomes similar to one another.

2 . A non-transitory computer-readable recording medium on which the periodic-combined-envelope-sequence generation program for causing a computer to function as the periodic-combined-envelope-sequence generation device according to claim 1 is recorded.

3 . A periodic-combined-envelope-sequence generation method, executing:

a spectral-envelope-sequence calculating for taking, as an input audio signal, a time-domain audio digital signal in each frame which is a predetermined time segment, and calculating a spectral envelope sequence of the input audio signal on the basis of time-domain linear prediction of the input audio signal; and

a periodic-combined-envelope generating for transforming the spectral envelope sequence to a periodic combined envelope sequence on the basis of a periodic component of the input audio signal in the frequency domain;

wherein the periodic-combined-envelope generating modifies the periodic combined envelope sequence based on a value that determines a mixture ratio between the spectral envelope sequence and the periodic component; and

the value that determines the mixture ratio is chosen such that the shape of the periodic combined envelope sequence and the shape of absolute values of a coefficient string which is transformed from the input audio signal in the frequency domain becomes similar to one another.

Assignments (1)

Priority Claims (1)

Continuity (6)

References Cited (39)