GEC-Marconi Avionics will announce the first application of its active noise-control (ANC) system for aircraft at the Paris air show. Unlike existing cabin noise-cancellation systems, which are synchronised with engine rotation to reduce the processing power required, the GEC system uses a technique known as fixed-frame sampling. All the major noise tones present in the cabin are measured and the "anti-noise" output required is calculated by a powerful digital signal-processor. Flight trials have been conducted in company and customer aircraft, GEC says.
Source: Flight International
