Patent ID: 6754337
Filing Date: 2004-06-22
Classification: H04M

Abstract:
In a telephone having a voice activity detector, the improvement comprising:a first voice activity detector having an input coupled to a microphone input and an output; a second voice activity detector having an input coupled to a line input and an output; a decode circuit coupled to the output of the first voice activity detector and to the output of the second voice activity detector and causing the telephone to enter a transmit state when the first voice activity detector indicates the presence of a voice signal and the second voice activity detector indicates the absence of a voice signal; wherein said first voice activity detector includes: a first comparator coupled to said microphone input for comparing an input signal to a first threshold and producing a first output signal indicative of the comparison: a second comparator coupled to said microphone input for comparing an input signal to a second threshold and producing a second output signal indicative of the comparison, wherein the first threshold is greater than the second threshold; a decoder for converting the first output signal and the second output signal into produce a binary number; a first accumulator summing the numbers from the decoder and producing a first total; and a third comparator for comparing the total with a second number and producing an output signal indicative of a voice signal being present when the sum exceeds the second number.