In
mathematics, a nonrecursive filter only uses input values like x
− 1 unlike recursive
filter
Filter, filtering or filters may refer to:
Science and technology
Computing
* Filter (higher-order function), in functional programming
* Filter (software), a computer program to process a data stream
* Filter (video), a software component tha ...
where it uses previous output values like y
− 1
In
signal processing
Signal processing is an electrical engineering subfield that focuses on analyzing, modifying and synthesizing ''signals'', such as sound, images, and scientific measurements. Signal processing techniques are used to optimize transmissions, ...
, non-recursive
digital filter
In signal processing, a digital filter is a system that performs mathematical operations on a sampled, discrete-time signal to reduce or enhance certain aspects of that signal. This is in contrast to the other major type of electronic filter, t ...
s are often known as Finite Impulse Response (FIR) filters, as a non-recursive digital filter has a finite number of coefficients in the impulse response h
Examples:
*Non-recursive filter: y
= 0.5x
− 1+ 0.5x
*Recursive filter: y
= 0.5y
− 1+ 0.5x
An important property of non-recursive filters is, that they will always be stable. This is not always the case for recursive filters.
Recursion