Echo cancellation for a communication device
Enabling and disabling the updating of an adaptive filter for echo cancellation of a communication device is discussed. In some embodiments, an echo canceler in a communication device may include an adaptive filter enabled to update responsive to a determination that a first condition is satisfied that there is no double talk detected on the communication device, and a determination that a second condition is satisfied based, at least in part, on a performance characteristic. The adaptive filter may be disabled from updating responsive to at least one of the first condition and the second condition not being satisfied. Described is disabling the adaptive filter from updating responsive to detecting a performance characteristic of the adaptive filter to fail to meet a condition indicating that the adaptive filter is diverging. The condition may be independent of whether double-talk is determined to be present on the communication device.
1. A method to reduce echo in a communication device, the method comprising:
measuring an echo return loss enhancement (ERLE) of an adaptive filter;
comparing the ERLE to a ERLE threshold; and
in response to the ERLE being less than the ERLE threshold and a double talk condition indicating double talk is not occurring, decreasing the ERLE threshold by a decay constant less than the ERLE threshold.
2. The method of claim 1 , wherein decreasing the ERLE threshold is in response to the ERLE being less than the ERLE threshold and a particular time elapsing without updating coefficients of the adaptive filter.
3. The method of claim 1 , further comprising filtering a signal using the adaptive filter to remove an echo signal included in the signal.
4. The method of claim 3 , wherein the filtered signal is configured to be provided to a speaker included in the communication device.
5. The method of claim 3 , wherein the signal is generated by a microphone included in the communication device.
6. The method of claim 3 , wherein the ERLE of the adaptive filter is based on the signal and an output of the adaptive filter.
7. The method of claim 3 , wherein the echo signal is an acoustic echo signal.
8. The method of claim 3 , wherein the echo signal is a line echo signal.
9. The method of claim 3 , wherein decreasing the ERLE threshold is in further response to a particular time elapsing without updating coefficients of the adaptive filter.
10. The method of claim 1 , wherein in response to the ERLE being more than the ERLE threshold, coefficients of the adaptive filter are updated.
11. The method of claim 1 , further comprising determining a trend of the echo return loss enhancement of the adaptive filter, wherein decreasing the ERLE threshold by the decay constant is further in response to the trend of the ERLE indicating that the ERLE is increasing.
12. The method of claim 11 , wherein determining the trend of the ERLE includes comparing a current ERLE measurement with one or more previous ERLE measurements.
13. The method of claim 1 , further comprising detecting the double talk condition for a first signal and a second signal of the communication device, wherein the double talk condition indicates that the double talk is not occurring.
14. The method of claim 1 , wherein in response to the ERLE being less than the ERLE threshold, the method further comprising disabling updating of coefficients of the adaptive filter.
15. At least one non-transitory computer readable media configured to store one or more instructions that when executed by at least one computing system performs the method of claim 1 .
16. A method to reduce echo in a communication device, the method comprising:
comparing an echo return loss enhancement (ERLE) of an adaptive filter to a ERLE threshold;
in response to the ERLE being more than the ERLE threshold, enabling updating of coefficients of the adaptive filter instead of decreasing the ERLE threshold by a decay constant less than the ERLE threshold when the ERLE is less than the ERLE threshold; and
after enabling updating of the coefficients, disabling updating of the coefficients in response to either double talk in the communication device or a trend of the ERLE indicating that the ERLE is decreasing.
17. The method of claim 16 , wherein enabling updating of the coefficients occurs in further response to a lack of double talk in the communication device and the trend of the ERLE indicating that the ERLE is increasing.
18. At least one non-transitory computer readable media configured to store one or more instructions that when executed by at least one computing system performs the method of claim 16 .
19. A method to reduce echo in a communication device, the method comprising:
determining a trend of an echo return loss enhancement (ERLE) of an adaptive filter;
detecting a double talk condition for the communication device;
measuring the ERLE of the adaptive filter;
comparing the ERLE to a ERLE threshold; and
in response to the double talk condition indicating double talk is not occurring, the ERLE being more than the ERLE threshold, and the trend of the ERLE indicating that the ERLE is increasing, updating coefficients of the adaptive filter instead of decreasing the ERLE threshold by a decay constant less than the ERLE threshold.
20. At least one non-transitory computer readable media configured to store one or more instructions that when executed by at least one computing system performs the method of claim 19 .