In the last time the study of random signals has became object of multidisciplinary researches. Random signals are used in solving a large class of problems. An important progress in the electronic packaging, telecommunications, in diagnosis systems is due to the study of high frequency random signals. By a random signal defined on a time set A with values in a Banach space X, we mean a family of random variables with values into a Banach space X indexed under a time parameter. But, the set of random variables can be endowed with a structure of probabilistic normed space. Moreover, a correspondence: a random signal to a function with values into probabilistic normed space is one to one and onto. In virtue to this correspondence we use probabilistic analysis to give methods for approximation of random signals, for describing types of periodicity and solving another problems in electronic packaging (Pecht et al., 1999) and measuring errors