Abstract: Various techniques are disclosed for improving packet loss concealment to reduce artifacts by using audio character measures of the audio signal. These techniques include attenuation to a noise fill instead of attenuation to silence, varying how long to wait before attenuating the extrapolation, varying the rate of attenuation of the extrapolation, attenuating periodic extrapolation at a different rate than non-periodic extrapolation, and performing period extrapolation on successively longer fill data based on the audio character measures, adjusting weighting between periodic and non-periodic extrapolation based on the audio character measures, and adjusting weighting between periodic extrapolation and non-periodic extrapolation non-linearly.

Abstract: Various techniques are disclosed for reducing artifacts generated by time compression. by adapting the time compression based on the state of the received audio. The amount of time compression may be bounded based on audio characteristics. Another feature provides a way of determining the most correlated portions of segments of audio. Voiced speech may be distinguished from unvoiced speech. Another feature provides a way of distinguishing between silence, voiced speech, and unvoiced speech. Time compression may be adapted during periods of lengthy silence. Another feature allows for reducing time compression during sensitive portions of the received audio. One or more of these features may be present in different embodiments.

Abstract: A communication system that includes multiple conferencing devices connected in a daisy-chain configuration is communicably connected to far-end conference participants. Multiple conferencing devices provide improved sound quality to the far-end participants by reducing aural artifacts resulting from reverberation and echo. The daisy-chain communication system also reduces the processing and transmission time of the near-end audio signal by processing and transmitting the audio signal in frequency domain. Each conferencing device in the daisy chain performs signal conditioning on its audio signal before transmitting it in the frequency domain to a mixer. The output signal of the mixer is converted back to the time domain before being transmitted to the far-end. The daisy-chain configuration also provides a distributed bridge to external communication devices that can be connected to each conferencing device.

Abstract: A communication system that includes multiple conferencing devices connected in a daisy-chain configuration is communicably connected to far-end conference participants. Multiple conferencing devices provide improved sound quality to the far-end participants by reducing aural artifacts resulting from reverberation and echo. The daisy-chain communication system also reduces the processing and transmission time of the near-end audio signal by processing and transmitting the audio signal in frequency domain. Each conferencing device in the daisy chain performs signal conditioning on its audio signal before transmitting it in the frequency domain to a mixer. The output signal of the mixer is converted back to the time domain before being transmitted to the far-end. The daisy-chain configuration also provides a distributed bridge to external communication devices that can be connected to each conferencing device.

Abstract: Various techniques are disclosed for reducing artifacts generated by time compression. by adapting the time compression based on the state of the received audio. The amount of time compression may be bounded based on audio characteristics. Another feature provides a way of determining the most correlated portions of segments of audio. Voiced speech may be distinguished from unvoiced speech. Another feature provides a way of distinguishing between silence, voiced speech, and unvoiced speech. Time compression may be adapted during periods of lengthy silence. Another feature allows for reducing time compression during sensitive portions of the received audio. One or more of these features may be present in different embodiments.

Abstract: Systems, methods, and devices for mixed voice and spread spectrum data signaling with enhanced concealment of data are disclosed. Audible artifacts may be reduced or suppressed in order to improve the audible quality of the sound. The distortion to the audio may be kept just below perceptibility, yet the data contained within the modulated signal is recoverable on the receiving side. The recovery of the data is robust to the impairments imposed by the communication channel. The disclosed systems, methods, and devices may be implemented in audio conferencing or video conferencing. Various embodiments of the present disclosure provide a data and voice mixer, which includes an improved spread spectrum data hiding transmitter. The transmitter may comprise a spreading encoder, a Phase Shift Keying (PSK) modulator, and a notch filter. A pseudo random switching pattern may be applied to a plurality of chip sequence generators in order to reduce or suppress an undesirable audible artifact.

Abstract: Various techniques are disclosed for improving packet loss concealment to reduce artifacts by using audio character measures of the audio signal. These techniques include attenuation to a noise fill instead of attenuation to silence, varying how long to wait before attenuating the extrapolation, varying the rate of attenuation of the extrapolation, attenuating periodic extrapolation at a different rate than non-periodic extrapolation, and performing period extrapolation on successively longer fill data based on the audio character measures, adjusting weighting between periodic and non-periodic extrapolation based on the audio character measures, and adjusting weighting between periodic extrapolation and non-periodic extrapolation non-linearly.

Abstract: Systems, methods, and devices for mixed voice and spread spectrum data signaling with spread spectrum data hiding with CDMA (Code Division Multiple Access) for three or more users. The disclosed systems, methods, and devices may be implemented in audio conferencing or video conferencing. Various embodiments of the present disclosure provide a data and voice mixer, which includes an improved spread spectrum data hiding transmitter. The transmitter may comprise a CDMA chip sequence generator and a spreading encoder. Different users may be accommodated by selecting different initializations for the registers of the CDMA chip sequence generator. Different spreading code may be used for different users which are near orthogonal to each other. In some embodiments, the CDMA chip sequence generator pseudo-randomly selects the chip sequence from one of a plurality of Gold chip sequence generators.

Abstract: A networked conferencing device includes at least one speaker, a display and a plurality of environmental sensors such as cameras, microphones, light level sensors, thermal sensors and motion sensors. The conferencing device receives environmental information from the sensors and processes this information to identify qualified events. The identified qualified events are then used to determine a next powered state for the conferencing device. If the next powered state is different than a current powered state, then the conferencing system transitions to the next powered state.

Abstract: A communication system that includes multiple conferencing devices connected in a daisy-chain configuration is communicably connected to far-end conference participants. Multiple conferencing devices provide improved sound quality to the far-end participants by reducing aural artifacts resulting from reverberation and echo. The daisy-chain communication system also reduces the processing and transmission time of the near-end audio signal by processing and transmitting the audio signal in frequency domain. Each conferencing device in the daisy chain performs signal conditioning on its audio signal before transmitting it in the frequency domain to a mixer. The output signal of the mixer is converted back to the time domain before being transmitted to the far-end. The daisy-chain configuration also provides a distributed bridge to external communication devices that can be connected to each conferencing device.

Abstract: A facsimile modem transmitter (40) uses pre-fax control signals, such as an answer tone or an FSK (frequency shift keying) modulation signal, to determine a channel spectral shape of the transmission media (14) before transmitting the fax data. The transmitter (40) determines average energy values of the pre-fax signals as a function of frequencies to determine the channel spectral shape. Using the channel spectral shape information, an appropriate transmission shaping filter (64, 66, 68) is chosen for use by the transmitter (40). This achieves better transmit and receive performance by compensating for roll-off on the transmission media (14), or channel, without the need to use specific training signals.

Abstract: An apparatus and method to characterize an input communication signal as being a voice, tone or noise signal is provided. The apparatus and method involve measuring variations of pitch over time from a sampled input signal. A minimum value of Average Magnitude Difference Function (AMDF) over a pitch range and an average variation value of the AMDF over sampled intervals are used to determine whether the signal is a voice signal, a tone or noise. Historical data of these values is maintained in a dual buffer arrangement and is used in the determination of signal type by detecting transitions.