Patent ID: 8503669

Claim:
In an audio system having a microphone, a speaker coupled to a source of audio output, and an echo canceller coupled to the speaker and microphone, a method for compensating for latency between the source of audio output and the speaker in echo cancellation performed by the echo canceller, wherein the echo canceller uses a reference signal derived from a signal from the source of audio output in echo cancellation, the method comprising: a) measuring a frequency dependent latency between the signal from the source of audio output and the speaker, wherein measuring the frequency dependent latency includes applying a broadband white noise calibration signal to the speaker, wherein the frequency dependent latency is caused by one or more components of the audio system that are characterized by a component latency that depends on the frequency of the signal, generating sound from the broadband white noise calibration signal with the speaker, capturing the sound with the microphone and converting the sound to a microphone signal, and comparing the broadband white noise calibration signal to the microphone signal; b) determining a frequency dependent delay amount from the frequency dependent latency; c) delaying the reference signal by the frequency dependent delay amount to produce a delayed reference signal; and d) using the delayed reference signal as the reference signal in the echo canceller.