The
Second Order Intercept Point, also known as the
SOI,
IP2, or
IIP2 (Input Intercept Point), is a measure of linearity that quantifies the second-order distortion generated by
nonlinear systems and devices. Examples of frequently used devices that are concerned with this measure are
amplifiers and
mixers. It is related to the
third-order intercept point, which is generally used for quantifying degree of nonlinearity of a nonlinear system or it can also be used to estimate the nonlinear products present at the output of such a system.