Skobeltsyn Institute of Nuclear Physics
Lomonosov Moscow State University

It is known that classical signal is able to carry out an infinite amount of information. The so-called threshold and up-limit boundaries on linear and spectrum density of real signal energy are introduced in this paper for limitation of mentioned infinite value. Some distinguishes are discussed of a real signal as an information carrier. It is shown where the informatics boundaries may take effect in the signal transmitters and receivers; the formulas for possible number of signal states and data exchange speed are found. The difference between noise and threshold limitations is demonstrated.