An active noise reduction system for aircrew helmets
Peter D. Wheeler, David Rawlinson, S. F. Pelc, T. P. Dorey · NASA STI Repository (National Aeronautics and Space Administration) · 1978
An active noise reduction system was developed for use in aircrew flying helmets in which the acoustic noise field inside the ear defender is detected using a miniature microphone and an antiphase signal is fed back to a communications telephone within the ear defender. Performance of the active noise reduction system in a laboratory trial simulating flight conditions is shown to be satisfactory.