A method of strongly decorrelating signals comprising processing input signals to determine delay and rotation parameters which implement at least one elementary paraunitary matrix. A method of the present invention which is performed in a semiconductor chip including a plurality of first elements, includes diagnosing the first elements by itself; and determining whether or not there is a faulty first element in the first elements based on diagnosis results from the first elements. In one embodiment of the invention, expression of an endogenous gene is activated or increased following integration into the cell, by non-homologous or illegitimate recombination, of a regulatory sequence that activates expression of the gene. The substrate is positioned in a CVD station, and one or more layers of a strengthening agent is deposited.