AM or FM radio decoder of VHF navigation signals in 108-137 MHz range e.g. for aircraft

摘要

The decoder system is used with an aircraft having one or more adjustable tuners (1) in the 108-137 MHz band to detect the FM and AM signals at the same frequency. Three may be used to cover the 118-137 MHz in AM, the 108-117.975 MHz of VHF omni-range (VOR) beacons and a single frequency in the 118-137 MHz range. The decoder (3) is a computer, programmed to set off an alphanumeric sequence after recognising a key word sequence or a preset modulation. The messages may be displayed on a LCD (4) which may be miniaturised and magnified by a lens. The screen may be strapped to a member of the cabin crew and is energy efficiency and vibration resistant. Information may also be printed or transmitted to a speaker (5) or earpieces.