Patent ID: 7856098
Filing Date: 2010-12-21
Classification: H04B

Abstract:
1. An echo cancellation method comprising: obtaining a plurality of samples from a first signal; computing a Discrete Cosine Transform (DCT) domain over the plurality of samples of the first signal to generate a plurality of DCT samples of the first signal; selecting one or more first coefficients from the plurality of DCT samples of the first signal; obtaining a plurality of samples from a second signal; computing a DCT domain over the plurality of samples of the second signal to generate a plurality of DCT samples of the second signal; selecting one or more second coefficients from the plurality of DCT samples of the second signal, wherein the one or more second coefficients are same coefficients as the one or more first coefficients; applying normalized cross correlation to values of the one or more first coefficients and values of the one or more second coefficients to generate normalized cross correlation values; determining a bulk delay of the echo based on the normalized cross correlation values; generating a third signal by subtracting an echo of the second signal from the first signal to cancel the echo using the bulk delay.