Abstract: For processing data signals representative of pixels, each of the pictures s scanned, column per column in successive horizontal bands each having a height equal to an entire fraction of the height of the picture, whereby a representation of the picture as pixels distributed in rows and columns is obtained, each band having a common predetermined number of rows. The picture is fractionated into mutually adjacent blocks of pixels each having M pixels in each of N mutually adjacent columns, M and N being predetermined integers and M being a simple multiple of the number of pixels in one column of a band and N being a whole fraction of the number of colums per image.

Abstract: A device for real time computing of a sum of terms having the form .SIGMAiT).qe((n-i)T) is suitable for use in an echo canceller for a data transmission system using code 2B 1Q. The device first transforms each of the successive estimated values of qe into transformed values qde which are powers of two, by adding or subtracting 1. The successive elementary products each obtained by a shift of h by an amount selected in response to the respective value of qde. The elementary products are summed in a register.