1. A method for discerning periodicities in signals, comprising the succession of steps of: sampling and pre-processing of a raw-signal in discrete succession of equally spaced slices of time, the sampling and pre-processing being respectively executed by a sampling device and an analog pre-processor; generating short-term characteristics vectors for such slice of time; grouping said-short term characteristics vectors into sets; obtaining at least one representative vector for each of said sets of short-term characteristics vectors; and estimating periodic structures using said representative vectors, wherein said generating, grouping, obtaining, and estimating are executed by computerized processors.