phase shift keying

Modulation scheme encoding all information into phase.

\begin{equation} s_i(t) = \Re\{Ag(t)e^{j2\pi (i-1)/M} e^{j2\pi f_c t}\} \end{equation}

signal constellation points are given by

\begin{equation} s_i1 = A \cos \left(\frac{2\pi (i-1)}{M} \right) \end{equation}
\begin{equation} s_i2 = A \sin \left(\frac{2\pi (i-1)}{M} \right) \end{equation}

All signals have equal energy, \(A^2\).

Based on the number of points in the diagram, \(M\) (because we need to map \(M\) messages onto coefficients in signal space), there are a few popular variants of PSK. Namely

binary phase shift keying
quadrature phase shift keying


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