| Abstract: | This report is a study of the development of an active, adaptive noise control system for a 4" I.D. duct. The study yielded the development of a series of circuits to be incorporated with a microprocessor in a continuous feedback loop. The four component circuits developed were: fixed and variable gain amplifiers, an AC/DC rectifier and a phase shift circuit. Each circuit was tested and operating characteristics and limitations for each component were determined. The complete system can attenuate signals between 90 hz and 1800 hz, with attenuations ranging from 28 to 34dB. |
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