The authors take into discussion some of the issues specific to signal’ reception. The received signal is transformed by the receiver into a time dependant function, a number or a Boolean variable. The study of such transformation requires the defiition of the functions group corresponding to the periodic signal, of the finite amplitude signals and the finite energy signals. The simplest model, and also the most important one for clearing the basic aspects of this issues, has imposed the assumption that the parasite influence of the received signal are additive. The method for the elimination of the additive noise and the extraction of the purified information will therefore be presented.
