AN EMBEDDED SYSTEM FOR ACTIVE LOCAL CONTROL OF NOISE IN THE BERTHING OF A HIGH SPEED PATROL

摘要

An embedded active noise control system has been developed to reduce low frequency noisein the aft berthing space of a high speed patrol craft. The system is fully autonomous with selfinitialization and monitoring capabilities. The system controls both high amplitude propellerblade-rate harmonic noise, as well as broadband noise caused by propeller cavitation andmachinery. One system, containing a loudspeaker, microphones, and control electronics, ismounted at the head end of each bunk. The only external connection to the system is a powercable. A local control strategy using an adaptive feedback algorithm provides a quiet zone at thehead of each bunk. Noise reductions of up to 20 dB at tones and 8, 15, and 5 dB in the 3 1, 63,and 125 Hz octave bands respectively have been measured at the head position of the bunks.Overall A-weighted level reductions of up to 6 dB have also been measured.