A figure of merit (expressed in dBm) that indicates the linearity and
distortion characteristics of a microwave component.
When referred to the output, the intercept point represents the point
where the extrapolation of the linear region of the
fundamentalpoweroutput curve and the spurious power level curve
intersect, when plotted on a loglog scale with output power as
ordinate and input power as abscissa. The most common output
intercept point is O IP_{3}, the output third order IP, sometimes called TOI;
in this case the spurious signal of interest is the third order intermodulation product.
Other less common intercepts measure second order (harmonic)
distortion level (IP_{2}), or higher product intermodulation level (e.g. IP_{5}
or IP_{7}).
Intercept points may also be referred to the input of a device. In this
case, It represents the point the extrapolation of the linear region of
the fundamentalpowerinput curve and the spurious power level curve
intersect, when plotted on a loglog scale with output power as
ordinate and input power as abscissa. Input intersect points can be
derived by subtracting the device gain from the output intercept point
value.
See also Third Order Intercept Point
