structural:scholar_edition, information:highlighting
Zero frequency component

Substituting ξ = 0 {\displaystyle \xi =0} in the definition, we obtain: f ^ (0) = ∫ − ∞ ∞ f (x) d x. {\displaystyle {\widehat {f}}(0)=\int _{-\infty }^{\infty }f(x)\,dx.}

The integral of f {\displaystyle f} over its domain is known as the average value or DC bias of the function.