Patent ID: 6415029
Filing Date: 2002-07-02
Classification: H04B

Abstract:
A double-talk detector for use in a communications unit, comprising:a down converter for receiving a signal and converting said signal to a base band frequency signal; a downlink voice activity detector coupled to said down converter for determining whether said base band frequency signal includes voice and continuing to indicate that said base band frequency signal includes voice for a predetermined period after said downlink voice activity detector ceases to determine that said base band frequency signal includes voice, said downlink voice activity detector comprising: leaky integrator for generating a current signal power estimate from an historical signal power and a current instantaneous signal power; and a noise floor estimator coupled to said leaky integrator and configured to apply a slow rise/fast fall for adaptively generating a noise floor estimate of said base band frequency signal using said current signal power estimate and generating a voice activity threshold based at least in part upon said noise floor estimate that is utilized in a comparison for said determining whether said base band frequency signal includes voice; a downlink peak power memory element configured to receive said base band frequency signal from said down converter and configured to store a plurality of samples of said base band frequency signal and determine a peak signal power estimate of said base band frequency signal over an interval of said plurality of samples; an uplink voice activity detector coupled to said downlink peak power memory element and said downlink voice activity detector, said uplink voice activity detector for detecting double-talk, said double-talk detected by said uplink voice activity detector when power of an outgoing voice signal is greater than a predetermined threshold above said peak signal power estimate of said base band frequency signal; a post processor coupled to said uplink voice activity detector and configured to mitigate double-talk effects when said uplink voice activity detector detects said double-talk; a second leaky integrator for generating a second current signal power estimate of said outgoing voice signal from a second historical signal power and a second current instantaneous signal power; and a second noise floor estimator coupled to said second leaky integrator and configured to adaptively generate a second noise floor estimate of said outgoing voice signal using said second current signal power estimate.