active power filter filter

adaptive spatial-temporal-spectral filter(ASTS filter)

band elimination filter band suppression filter

band suppression filter band elimination filter

band-rejection filter (=band elimination filter)

composite filter beds biological aerated filter

DBGF filter (deep-bed glass fibre filter)

filter paper filter

fritted glass filter sintered glass filter

Gauss Hermite filter-Kalman filter

Gaussian Sum Filter-Kalman Filter GSF-KF

maximally-flat filter (Butterworth filter)

Polynomial Predictive Filter-Kalman Filter PPF-KF

resistance-capacitance filter(RC filter)

revoling leaf type filter + vacuum filter

sintered glass filter fritted glass filter

(+)Digital matched-filter

(fuzzy)BCK-filter

(The symbol is abbreviated) filter