Patent ID: 6611601
Filing Date: 2003-08-26
Classification: H04M

Abstract:
An echo sound signal suppressing apparatus for suppressing an echo sound signal to ensure speech communication between a far-end speaker and a near-end speaker, comprising:a loudspeaker for outputting a first sound in its loudened state after converting a first sound signal from said far-end speaker to said first sound, said loudspeaker having an input terminal connected to a communication line to have said first sound signal pass therethrough, said first sound signal comprising a far-end speaker sound signal component indicative of a first sound from said far-end speaker, and a first noise signal component indicative of far-end outside noises generated in the neighborhood of said far-end speaker, said first noise signal component having a power value; a microphone for inputting three different sounds before converting said three different sounds to a second sound signal, said three different sounds comprising a second sound from said near-end speaker, an echo sound indicative of said first sound reflected under the influence of the objects outside said near-end speaker, and near-end outside noises generated in the neighborhood of said near-end speaker, said second sound signal comprising a near-end speaker sound signal component indicative of said second sound from said near-end speaker, an echo sound signal component indicative of said echo sound, and a second noise signal component indicative of said near-end outside noises generated in the neighborhood of said near-end speaker, said second sound signal having a power value, and said second noise signal component having a power value; echo replica sound signal producing means for producing an echo replica sound signal with said first sound signal and said second sound signal, said echo replica sound signal having a power value; difference signal producing means for producing a difference signal by subtracting said echo replica sound signal from said second sound signal, said difference signal comprising said near-end speaker sound signal component and a difference signal component indicative of subtracting said echo replica sound signal from said second sound signal, and having a power value; first power value calculating means for calculating said power value of said second sound signal; second power value calculating means for calculating said power value of said echo replica sound signal produced by said echo replica sound signal producing means; echo sound suppressing means for suppressing said echo sound difference signal component outputted from said difference signal producing means to a minimum level with said power value of said second sound signal calculated by said first power value calculating means and said power value of said echo replica sound signal calculated by second power value calculating means with said near-end speaker sound signal component being allowed to pass therethrough, said echo sound suppressing means having an output terminal to said communication line to output said near-end speaker sound signal component under the condition that said echo sound signal component is reduced to its smallest level.