TELEPHONE HAVING FOUR VAD CIRCUITS

摘要

Voice activity detectors 81, 83, 85, 87, individually weighted, are provided at each input and each output of a telephone 80 for reliably controlling echo cancelling circuitry within the telephone. Voice activity is detected by comparing a signal with two thresholds and producing data representing the energy of the signal. The data, in binary form, is compared with thresholds to determine voice activity. In accordance with another aspect of the invention, the thresholds are adjusted based upon statistical information. In accordance with another aspect of the invention, the data can be weighted to provide an indication of the quasi-RMS energy of an input signal.