Abstract: An estimate is made of the power of a speech portion of a speech signal that includes speech portions separated by non-speech portions, the power for the speech portion being estimated based on a power envelope that spans the speech portion. The gain of an automatic gain control is not adjusted during the speech portions.

Abstract: Whitening is performed on at least a far-end communication signal to reduce a number of averages that must be calculated with respect to a cross-correlation process applied to the far-end signal and a near-end signal. The far-end signal is delivered to a near-end user device without having been whitened. The result of the cross-correlation process is used to estimate a bulk delay of one of the near-end and far-end signals relative to the other.

Abstract: An estimate is made of the power of a speech portion of a speech signal that includes speech portions separated by non-speech portions, the power for the speech portion being estimated based on a power envelope that spans the speech portion. The gain of an automatic gain control is not adjusted during the speech portions.

Abstract: The presence of a voice in an audio signal is detected by sampling frequency components of the audio signal during a window that starts when a power of the audio signal reaches a predetermined threshold and stops when the audio signal's power drops below the predetermined threshold. An array of elements is generated based on the sampled frequency components. Each element in the array corresponds to a time-based sum of frequency components. Whether the audio signal corresponds to a voice is determined using one or values calculated from the generated array. The value may correspond either to a frequency-based sum of array elements or to the window. The calculated values are analyzed using fuzzy logic which generates a measure of a likelihood that the audio signal is a voice.