Texas Instruments Corporation

Telogy Networks, Inc.

Daniel C Thomas

Dunling Li

Gokhan Sisli

Satish Kumar M Mundra

Providing interoperability on a voice communication network by detecting incompatible bit packing payload formats of ADPCM encoded voice data signals in an encoder/decoder. A mismatch of bit packing formats between little endian format and big endian format is determined by detecting the occurrence of ADPCM code words of interest in the decoded voice data stream out of the encoder/decoder. The invention may be applied to an ITU G.726 encoder/decoder.

Interoperability of ADPCM encoded voice communications

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.

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

A method to reduce the amount of bandwidth used in the transmission of digitized voice packets is described. The method is used to reduce the number of transmitted packets by suspending transmission during periods of silence or when only noise is present. The system determines if a background noise update is warranted based on human auditory perception factors instead of an artificial limiter on excessive silence insertion descriptor packets. The system searches for characteristics in the perceptual changes of background noise instead of analyzing speech for improved audio compression. The invention weighs factors affecting the perception of sound including frequency masking, temporal masking, loudness perception based on tone, and auditory perception differential based on tone.

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Germantown, MD, United States of America

Daniel C Thomas