WActive filter
WBand-pass filter
WBand-stop filter
WBridged T delay equaliser
WButterworth filter
WCommensurate line circuit
WCrystal filter
WEqualization (audio)
WFilter bank
WFrequency dependent negative resistor
WGabor filter
WGammatone filter
WGaussian filter
WGyrator
WHigh-pass filter
WKalman filter
WLattice delay network
WLattice phase equaliser
WLeapfrog filter
WLinkwitz–Riley filter
WMechanical filter
WMPX filter
WOptimum "L" filter
WPrototype filter
WQ factor
WTop-hat filter
WWaveguide filter
WFile:Constant k order 2.PNG
WFile:Constant k order 5.png
WFile:Image filter terms.svg