An input device receives sets of input data to be stored in a correlation matrix memory. A sampler derives, from each set of input data, a respective set of tuples, and a coder codes each of the tuples, which are then combined for the respective set of input data. A separator generator generates for each set of input data a respective, associated, unique separator, which is stored with its respective set of input data. For each set of input data, the respective combined coded tuples and the respective unique separator are applied to the correlation matrix memory as a row address and as a column address, or vice-versa.