SELECTIVE ACTIVE CANCELLATION SYSTEM FOR REPETITIVE PHENOMENA

摘要

A cancellation system including a processor having single adaptive filters 44, 46 adapting its filtering characteristic as a function of a phenomena signal and phenomena timing signal and a phase circuit to maintain the adapting of the filtering characteristics within 90 degrees phase of the phenomena signal. The phase circuit has the capability to measure the delays of the processor and the environment. The system is fast enough to use only an error sensor and can be manually or automatically tuned.