Abstract: A distributed intelligence conferencing system having a plurality of conferencing nodes to connect groups of participants to a conference. Each of the conferencing nodes provides for the connection of one or more participants to the conference. Each node includes a DSP for distributed signal processing. The nodes DSP includes: A signal measuring device for measuring features of the signals from each of the participants. A single core speaker tracking algorithm identifies the active speaker on a local node based upon the relative signal features of each of the number of participant input signals. A communication device communicates the measured signal features for the active local participant input signals only to all other conferencing nodes. A multi core speaker tracking algorithm compares the features of the signals from the speakers on the local node with the features of the signals from the speakers on other nodes.

Abstract: A distributed conferencing system having a plurality of conferencing nodes to connect groups of participants to a conference. Each of the conferencing nodes provides for the connection of one or more participants to the conference. Each node includes a DSP for distributed signal processing. The node DSP includes: A signal measuring device for measuring features of the signals from each of the participants, such as power, zero crossing rate and short term energy and voice activity determination and feature extraction from the signals of the participants connected to each node. Each node has a single core speaker tracking algorithm for determining the relative features of each of the number of participant input signals. The speaker tracking compares the characteristics of the speakers of the core and determines which speakers are to be included and which speakers are to be excluded from presentation to the other nodes in the conference.

Abstract: A distributed conferencing system has a plurality of conferencing nodes to connect groups of participants to a conference. Each of the conferencing nodes provides for the connection of one or more participants to the conference. Each node includes a DSP for distributed signal processing. The node DSP includes: A signal measuring device for measuring features of the signals from each of the participants, such as power, zero crossing rate and short term energy. The nodes include voice activity determination and a communication device for communicating the measured signal characteristics for a plurality of participant input signals to all other conferencing nodes. Muting means for muting individual participant input signals so that only selected signals are transmitted over the conference bus to the other participants.

Abstract: An overflow problem of LSF quantization in G.729 Annex B speech encoding. Preferred embodiments fix the problem with default or limited random variable assignments or flagging the overflow and adjusting the frame encoding such as by limiting spectral components or changing quantization targets.

Abstract: A method of initializing an ITU Recommendation G.729 Annex B compliant voice activity detection (VAD) device is disclosed, having the steps of (1) determining a first set of running average background noise characteristics in accordance with Recommendation G.729B; (2) determining a second set of running average background noise characteristics; and (3) substituting the second set of running average background noise characteristics for the first set when a specific event occurs. The specific event is a divergence between the first and second sets of running average background noise characteristics.

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.

Abstract: A method of discriminating noise and voice energy in a communication signal. A signal is measured in a plurality of block periods, which are sampled to obtain a measurement of the block energy value for the signal. The blocks are compared to a noise threshold and to a voice threshold to discriminate between noise and voice. The thresholds for noise and voice are periodically updated based on the minimum and maximum energy levels measured for block energies. In a preferred embodiment, the voice energy threshold and noise energy threshold values are updated according to a formula where the revised thresholds are based upon a factor of the minimum and maximum energy levels of the current block and the most recent past block and the average energy of the previous blocks. Updating of threshold levels allows for more accurate estimation of noise and voice during changes in either noise, voice or both to avoid missclassification of noise and/or voice.

Abstract: A system and method for maintaining acceptable perceived sound quality while achieving desired bandwidth savings in voice-over packet networks that use signal energy level dependent thresholds. The method utilizes only the block energy of the input signal to discriminate between active signal, such as voice, facsimile tone, touch tone or dial tone, and background noise. The discrimination algorithm is adaptive to changes in signal energy levels. The method is designed to accommodate a large dynamic range of signal volumes and is reliable under different background noise conditions. The method includes a robust active signal and noise level estimation algorithm that prevents threshold divergence. A speech-smoothing scheme is used to prevent misclassifying weak active signals as background noise. The complexity of the bandwidth saving method is linear with respect to the input signal length.