US 7,031,916 B2 · Method for converging a G.729 Annex B compliant voice activity detection circuit

Abstract

A method of initializing an ITU Recommendation G.729 Annex B voice activity detection (VAD) device is disclosed, having the steps of (1) extracting a set of parameters from a signal that characterize the signal; (2) calculating an energy measure of the signal from the set of parameters; (3) comparing the energy measure with a reference value; (4) determining an initial value for an average of a noise characteristic of the signal; and (5) counting the number of times the energy measure equals or exceeds the reference level. Also disclosed is a method of converging an ITU Recommendation G.729 Annex B voice activity detection (VAD) device, having the steps of: (1) determining a noise identification threshold value; (2) comparing a number of energy measures of a signal to the noise threshold value; (3) determining a first value representing an average of the number of energy measures, when the energy measure is less than the noise threshold, wherein only the energy measures of the number of energy measures having values less than the noise threshold value are used to determine the first value; (4) determining a second value representing an average of the number of energy measures; and (5) substituting the first value for the second value when a specific event occurs, indicating the divergence of the two values.

Claims17

Dependent claims

A method for improving estimates of average background noise energy in a G.729 Annex B compliant voice activity detection (VAD) device by substituting supplemental average background noise parameters derived according to a supplemental algorithm for a running average of background noise parameters derived according to G.729 Annex B, comprising:

determining a maximum full-band energy, Emax, and a minimum full-band energy, Emin, from a plurality of incoming noise frames during a current period, i;
generating a noise threshold, Tnoise, i+1, for the next period, such that Tnoise, i+1=min(2*min(T1, T2), −21 dBm), where T1=Emin+(Emax−Emin)/32, T2=4*Emin, Emax=the maximum block energy measured during the current updating period, and Emin=the minimum block energy measured during the current updating period:
determining a full-band energy of a current incoming noise frame, Ei;
updating supplemental average background noise parameters to the current period:
comparing the supplemental average background noise parameters of the current period to the running average of background noise parameters derived according to G.729 Annex B;
and
if the supplemental average background noise parameters of the current period diverge from the running average of the background noise parameters derived according to G.729 Annex B, then substituting the supplemental average background noise parameters of the current period for the running average of the background noise parameters derived according to G.729 Annex B.

4 more elements

Dependencies are inferred from the claim text.

Method for converging a G.729 Annex B compliant voice activity detection circuit

Life of this patent

Method for converging a G.729 Annex B compliant voice activity detection circuit

Life of this patent

Abstract

Claims17