Patent ID: 9697847
Date: 2017-07-04
CPC Classifications: G10L,H04M

Claim:
1. A method for processing an acoustic signal, comprising: receiving a first acoustic signal in the time domain; converting the first acoustic signal in the time domain into a digital audio signal in a sub-band frequency domain; reserving a first frequency band of the digital audio sub-band frequency signal having a plurality of frequency bands using a frequency band reservation module that includes a digital signal processor and a plurality of control multipliers, wherein a first control multiplier includes a first sub-band frequency input coupled to a first input of the digital signal processor and a second input coupled to a first output of the digital signal processor and a second control multiplier includes a first input coupled to a second input of the digital signal processor and a second input coupled to a second output of the digital signal processor; transforming the sub-band frequency digital audio signal including the first frequency band into a second acoustic signal using an acoustic transducer; transforming a third acoustic signal derived from the second acoustic signal and a near end signal into a mixed sub-band frequency signal; transforming the sub-band frequency digital audio signal into a modified sub-band frequency signal; generating a sub-band frequency error signal in response to the modified sub-band frequency signal by subtracting the modified sub-band frequency signal from the mixed sub-band frequency signal; generating a speech activity-indicator in a first reserved frequency band of the mixed sub-band frequency signal in response to the presence of speech activity; generating an echo activity indicator by subtracting the sub-band frequency error signal from the mixed sub-band frequency signal; logically ANDing the speech activity indicator and the echo activity indicator to generate a double-talk activity indicator that indicates the presence or absence of double-talk; generating a second modified digital audio sub-band frequency signal in response to the double-talk activity indicator; converting the second modified digital audio sub-band frequency signal into a modified time domain signal; and transmitting the modified time domain signal to a receiver for use by a user.