Audio communication device and method using fixed echo cancellation filter coefficients

1. An apparatus, comprising:

a downlink;

and

an echo cancellation module configured to filter a first signal on the downlink using a dynamic set of filter coefficients and one static set of filter coefficients selected from a static first set of filter coefficients and a static second set of filter coefficients to generate a second signal, and to generate a third signal based on a difference between the second signal and a fourth signal that is based on sound received by a first microphone,

wherein the echo cancellation module is configured to use the static first set of filter coefficients for a first mode of operation and the static second set of filter coefficients for a second, different mode of operation and wherein the one static set of filter coefficients for the first mode of operation improves a single talk echo performance by about 5 to 10 dB compared to filtering the first signal using only the dynamic set of filter coefficients.

2. The apparatus of claim 1 , wherein values of the static first set of filter coefficients do not depend upon values of a second set of filter coefficients.

3. The apparatus of claim 1 , wherein the apparatus is further configured to generate a sixth signal based on a difference between a fifth signal and the third signal.

4. The apparatus of claim 3 , wherein the apparatus is further configured to wirelessly transmit a signal based on the sixth signal to a communication network.

5. The apparatus of claim 1 , further comprising a read-only memory storing the first set of filter coefficients.

6. The apparatus of claim 1 , further comprising an electrically-erasable programmable memory (EEPROM) storing the first set of filter coefficients.

7. The apparatus of claim 1 , wherein the echo cancellation module comprises a processor.

8. The apparatus of claim 1 , further comprising a second microphone, wherein a fourth signal is further based on sound received by the second microphone.

9. The apparatus of claim 1 , further comprising a second speaker coupled to the downlink.

10. The apparatus of claim 1 , wherein the first mode of operation is a handset mode and the second mode of operation is a handsfree mode.

11. A method, comprising:

filtering a first signal on a downlink of an audio communication device using a dynamic set of filter coefficients and a static first set of filter coefficients to generate a second signal;

generating a third signal based on a difference between the second signal and a fourth signal that is based on sound received by a first microphone of the audio communication device; and

wherein filtering the first signal includes selecting the static first set of filter coefficients from a first static first set of filter coefficients for a first mode of operation and a second, different static first set of filter coefficients for a second, different mode of operation, wherein selecting the static first set of filter coefficients for the first mode of operation improves a single talk echo performance by about 5 to 10 dB compared to filtering the first signal using only the dynamic set of filter coefficients,

12. The method of claim 11 , further comprising generating sound from a speaker of the audio communication device based on the first signal.

13. The method of claim 11 , wherein values of the first set of filter coefficients do not depend upon values of a second set of filter coefficients.

14. The method of claim 11 , further comprising generating a sixth signal based on a difference between a fifth signal and the third signal.

15. The method of claim 14 , further comprising wirelessly transmitting a seventh signal based on the sixth signal to a communication network.

16. The method of claim 11 , further comprising storing the first set of filter coefficients in a read-only memory of the audio communication device.

17. The method of claim 11 , further comprising storing the first set of filter coefficients in an electrically-erasable programmable memory (EEPROM) of the audio communication device.

18. The method of claim 11 , wherein the fourth signal is further based on sound received by a second microphone of the audio communication device.

19. An apparatus, comprising:

a first speaker coupled to a downlink;

a first microphone; and

an echo cancellation module configured to filter a first signal on the downlink using a static first set of filter coefficients to generate a second signal, and to generate a third signal based on a difference between the second signal and a fourth signal that is based on sound received by the first microphone,

wherein the echo cancellation module is further configured to filter the first signal using a dynamic second set of filter coefficients that change over time to generate a fifth signal, and

wherein addition of the static first set of filter coefficients in the echo cancellation module is configured to improve a single talk echo performance by 5 to 10 dB compared to filtering the first signal using only the dynamic set of filter coefficients,

20. A method, comprising:

filtering a first signal on a downlink of an audio communication device using a static first set of filter coefficients to generate a second signal; and

generating a third signal based on a difference between the second signal and a fourth signal that is based on sound received by a first microphone of the audio communication device,

filtering the first signal using a dynamic set of filter coefficients that change over time to generate a fifth signal,

wherein addition of the static first set of filter coefficients in the filtering is configured to improve a single talk echo performance by 5 to 10 dB compared to filtering the first signal using only the dynamic set of filter coefficients.