DISPOSITIVO PER OTTENERE UN FILO DOPPIO IN PARTICOLARE UN FILO RINFORZATO

An audio signal processor treats a digitally encoded signal. Units (3, 12) sample the encoded signal and units (8, 13) calculate from the sampled values a correlation function relevant to a particular time frame. The function value serves to control an adaptive echo cancellation algorithm. The sampled signal portions are truncated (2, 5) so that only the arithmetic sign bit of each signal portion contributes to the function calculation. An incoming signal sample is initially treated in an extraction block arranged to determine the arithmetic sign relevant to that signal, the resulting sign bits being fed in sequence to a shift register arranged to store a predetermined number of sign bits. Outputs are provided from selected locations in the register in accordance with a control logic select circuit.