Phase shift

Phase shift

The difference ${\displaystyle \varphi (t)=\varphi _{G}(t)-\varphi _{F}(t)}$ between the phases of two periodic signals ${\displaystyle F}$ and ${\displaystyle G}$ is called the phase difference or phase shift of ${\displaystyle G}$ relative to ${\displaystyle F}$. At values of ${\displaystyle t}$ when the difference is zero, the two signals are said to be in phase; otherwise, they are out of phase with each other.