TELEPHONE APPARATUS AND A COMMUNICATION METHOD USING SUCH APPARATUS

摘要

In accordance with a first aspect of the present invention there is provided a telephone apparatus including a transmitter portion and a receiver portion, an input transducer for converting input audio signals into electrical signals, a connectable input link between the input transducer and the transmitter portion to deliver whenconnected an input electrical signal to the transmitter portion to be transmitted by the transmitter portion, an output transducer for converting an output electrical signal into an audio signal and a connectable output link between the receiver portion and the output transducer for delivering when connected an output signal to the output transducer, optionally an echo cancellation circuitry portion adapted to sample the output signal and produce an echo replica signal, optionally a mixer included in the input link for mixing an echo replica signal produced by the echo cancellation circuit with an input signal produced by the input transducer, and an echo suppression circuitry portion including detector means for producing a first magnitude signal which represents a magnitude property of a first smple of an output signal So in the output link and a second magnitude signal which represents a magnitude property of a second sample of an input electrical signal Si in the input link between the mixer and the transmitter portion, an analyser, connected to receive inputs comprising the first and second magnitude signals from the detector means, for measuring a relationship between thefirst and second magnitude signals and for producing a control signal when the relationship exceeds a threshold, wherein the detector means is operable periodically to analyse characteristics of the signal So to estimate the amount of background noise in the signal So and to pass as an input to the analyser a signal representing the estimated amount of backgroudn noise wherein the threshold above which the analyser produces an output control signal is set adaptively by the analyser dependent on the estimated background noise.