Patent ID: 6041125
Filing Date: 2000-03-21
Classification: G10K

Abstract:
An active acoustic wall for absorbing sound waves across a broadband frequency range, comprising:a perforated plate comprising at least one selected from the group consisting of a perforated member and a porous material, said perforated plate having a front side and a back side;a back wall spaced from said back side of said perforated plate such that a space is formed between said back side of said perforated plate and said back wall;a plurality of partition plates dividing said space between said perforated plate and said back wall into a plurality of sections;oscillation plates provided within each of said sections, respectively;driving units for driving said oscillation plates;two sound pressure detectors provided within each of said sections providing first and second signals; anda signal processing unit connected with said sound pressure detectors and said driving units, receiving each of said first and second signals, calculating the impedance of each of said sections, comparing the impedance to a predetermined value, and providing an output signal to each of said driving units such that each of said oscillation plates oscillates and creates an impedance which approximates said predetermined value.