Abstract: A device for processing digital data. A module (M2, M3) produces on a data vector of the frequency domain Z(k), wherein K varies from 0 to N?1, a convolution with a function U, convolution which corresponds to a cancellation in the time domain of the samples of the inverse transform of Z(k). The function U is in the form: U(k)=sin c(k?k0/2.e)?j?(?(k?k0/2.P(k)), wherein K0 is a constant integer and P(k) a weighting window symmetrical about k0.

Abstract: In order to cancel echo on several sound signal channels, the method consists in generating on each channel a synthetic signal having the spectral characteristics of a white noise; computing the frequency masking thresholds in several adjacent frequency bands using auditory perception properties; bringing in each frequency channel the synthetic signal level to the associated masking threshold value, so as to obtain an auxiliary signal, which is added to the signal associated with the loudspeaker of the channel concerned; supplying the resulting signal to an adaptive filter; adding the output signals of the associated adaptive filters to each microphone channel; subtracting the resulting signal received by the microphone of this channel; deducing an estimation error, on the basis of which the coefficients of the adaptive filters associated with this channel are corrected.