Definition:Filtering Function
Jump to navigation
Jump to search
Definition
The filtering function is the real function $\operatorname {sinc}: \R \to \R$ defined as:
- $\forall x \in \R: \map {\operatorname {sinc} } x := \dfrac {\sin \pi x} {\pi x}$
where $\sin$ denotes the (real) sine function.
Graph of Filtering Function
The graph of the filtering function is illustrated below:
$2$ Dimensional Form
Let $\operatorname {sinc}: \R \to \R$ denote the filtering function.
The $2$-dimensional form of $\operatorname {sinc}$ is defined and denoted:
- $\forall x, y \in \R: \map {\operatorname { {}^2 sinc} } {x, y} := \map {\operatorname {sinc} } x \map {\operatorname {sinc} } y$
Also known as
The filtering function is also known as the interpolating function.
The filtering function of $x$ is often voiced sinc $x$, exactly as written.
Warning
The filtering function is also known as the interpolating function.
The filtering function $\map {\operatorname {sinc} } x$ is not the same as the real function $f$ defined as $\forall x \in \R: \map f x = \dfrac {\sin x} x$, which is depicted below:
Sources
- 1978: Ronald N. Bracewell: The Fourier Transform and its Applications (2nd ed.) ... (previous) ... (next): Frontispiece
- 1978: Ronald N. Bracewell: The Fourier Transform and its Applications (2nd ed.) ... (previous) ... (next): Chapter $4$: Notation for some useful Functions: Summary of special symbols: Table $4.1$ Special symbols
- 1978: Ronald N. Bracewell: The Fourier Transform and its Applications (2nd ed.) ... (previous) ... (next): Inside Back Cover