Abstract: A method and apparatus are provided for detecting a relatively constant frequency signal on a communication channel. The method includes the steps of detecting sign changes of the signal on the channel and determining that the signal is substantially the only signal present on the channel when an average time interval between positive-going sign changes substantially equals an average time interval between negative-going sign changes.

Abstract: A method and apparatus are provided for controlling a gain of an audio stream. The method includes the steps of collecting a plurality of samples of the audio stream, squaring a magnitude of a representation of at least some samples of the collected plurality of samples, summing the squared representations and adjusting a magnitude of the plurality of samples by a value equal to a square root of a ratio between the sum and a predetermined reference value.