Filter
A
filter is a membrane or layer that is designed to block certain things (objects or substances) whilst letting others through. Filters are often used to remove harmful substances from
air or
water, for example to reduce
air pollution or to make contaminated air breathable with a
gas mask. Very common is the
coffee filter.
In
mathematics, a
filter is a
subset of
power set with certain properties. See
filter (mathematics).
A
filter is a short-form of
mail filter.
An
electronic filter is an
electrical circuit whose frequency response or
transfer function is non-uniform. In other words, its gain or attenuation depends on
frequency.
An
analog filter is a form of filter (usually electronic)
that uses
analog circuitry in its implementation.
A
digital filter is an algorithm for processing numeric data, and which can also be used in
digital signal processors to function in a similar way to an electronic filter. Digital filters are now used in many modern appliances, such as CD players, radio tuners, TVs etc.
An
audio filter is a type of filter that is used for processing audio signals in appliances such as CD players,
synthesizers or
sound effects.
A
1990s industrial rock band is called
Filter.
An optical filter removes/only passes certain wavelengths of light, e. g.
Infrared filter, ND filter, UV filter
See also:
Glossary of filter terms\n