Determination of the splitting function by signal spectrum

In modern telecommunication, spread spectrum techniques often used. Special case of spread spectrum – spectrum splitting. This technique is characterized by signals whose energy is concentrated in two or more spaced portions of the spectrum. If there is a modulating subcarrier in modulation function, and this subcarrier is shorter then duration of transmitted information symbols by a multiplicity factor, then this function provide spectrum splitting. The frequency of this subcarrier called subcarrier frequency, and function of this subcarrier called subcarrier frequency function or splitting function. The main problem of this article is the ability to determine by which split function the original spectrum of the unknown signal has obtained, because during the analysis it is necessary to understand general patterns of the signal formation. The article discusses various signals with spectrum splitting. There is an overview of the methods of spectrum splitting obtained for different types of modulation (phase, amplitude, frequency) and some splitting functions (harmonic, meander and functions of periodic triangular pulses). The spectrums of the signals obtained by different splitting functions are studied and conclusions has drawn on how to determine the splitting function and the type of modulation for the spectrum splitting of an unknown signal.