Active Filters Applied to Helicopter Noise Reduction

摘要

Two active filter resonators of the negative feed-back type are evaluated. Claimed stability in literature and design formulas are verified by an active filter breadboard. Requirements for a passive L-C filter, developed for avionics equipment, were used as design objectives. The desired response was realized using two resonator types. A hybrid version of the active filter was designed and fabricated to establish that microminiaturization was feasible without any degradation in performance. (Author)