Patent ID: 8892430
Filing Date: 2014-11-18
Classification: G10L,G11B

Abstract:
1. A noise detecting device for detecting an impulsive noise of a digital voice signal, the noise detecting device comprising: a residual signal calculating unit configured to calculate a residual signal that is obtained by removing a prediction signal, which is acquired by performing a linear prediction for an input digital voice signal, from the input digital voice signal; a difference signal calculating unit configured to calculate a first difference signal that indicates an amplitude difference between a residual signal at a current sample timing and a residual signal at any sample timing before the current sample timing; and a determining unit configured to determine whether or not an impulsive noise is present on the basis of an amplitude of the first difference signal at the current sample timing, and an amplitude of a second difference signal, the second difference signal indicating an amplitude difference between a residual signal at a sample timing within a predetermined duration before or after the current sample timing and a residual signal at any sample timing before the sample timing within the predetermined duration, wherein the residual signal calculating unit includes the determining unit calculates a ratio of an absolute value of the amplitude of the first difference signal at the current sample timing to an amplitude of the second difference signal having a maximum absolute value of an amplitude among difference signals within the predetermined duration before and after the current sample timing, and determines whether or not an impulsive noise is present by judging whether or not the ratio of the amplitudes is equal to or larger than a threshold value.