Spectral correlation function of basic analog and digital modulated signals

Spectral correlation function (SCF) is a powerful tool to study cyclostationary signals. It can be used to analyze and extract information from modulated signals in noise according to their cyclostationarity. In this paper we investigate SCF features of several basic modulated signals from point view of modulation recognition and parameter estimation. SCFs of modulated signals are given according to their definitions, then their similarity and differences are compared by 3D diagrams, contours, and specific profiles. Periodicity in time domain will lead to peaks in SCF figure whose locations indicate carrier frequency and baud rate. Distributions of SCFs in dual frequency plane are sources to extract features for recognize modulation. Several examples are given to illustrate the value of SCF and conclusion of this paper.