Today GEMELLI is the Italian leader for the design and supply of aircraft internal communication equipment and systems. GEMELLI devices can assure clear communication performances even when they are required to operate in very severe noise environmental conditions, as they are fully integrated with active noise control technologies.
During the years 2000 the marketing interest for GEMELLI integrated A.N.R. communication systems grew up substantially. Some customers like the Italian Army decided to upgrade all the major combat helicopter ICS adopting the GEMELLI WonderCom family of equipment to protect the flying personnel and to obtain clear communication in high noise environment. The level of high intelligible communication achieved by the applications mentioned above was the initial step for generating other kinds of worldwide interests for GEMELLI product lines. Some of these were the collaboration program with Lockheed Martin for the development of advanced fighter flight helmets and the upgrade of large Russian helicopters internal communication systems required during operations in the west.
One of the main problems arising today in an aircraft, where the communications intelligibility is vital for the success of the mission, is the fact that such communications are often jeopardized by the ambient noise going through the headsets protection materials or entering the microphones and running through the communication lines. In both cases the communication message reaching the personnel’s ears is distorted or only partially understandable.
The A.N.R.A.C.S. (Active Noise Reduction Aircraft Communication System) gives a complete solution to the communication problems as it can control and strongly reduce both the ambient and the communication lines noise (at least 40 dBA).
It is clear that the system also offers a superior protection to the people in the aircraft, because it allows them to operate in a very comfortable trim even when more than 100 dB noise is present in the aircraft cabin.
THE OPERATING PRINCIPLE
The performances of the system are assured by the two following electronic features:
- A.N.R. (Active Noise Reduction) is an electronic device capable of strongly reducing the noise passing through the headsets protection materials by generating a signal that is equal in frequency and amplitude and opposite in phase to the noise signal. The generated signal comes from the very headsets loudspeakers. The A.N.R. electronic card recognizes the communication signal coming from the microphone through the intercom line but does not affect it.
- M.A.N.P. (Microphone Active Noise Processor) is an electronic device that acts in conjunction with the presented I.C.S. and can discriminate the communication signal (voice) among all other signals reaching the microphones. M.A.N.P. keeps the line OFF when only noise is present and ON when a voice signal is activated. In this case the voice content is detected and maintained at the original level, while the noise component is strongly reduced. The signal to noise ratio achievable is then better than 40 dB also in presence of noise level comparable to signal.