VHF air-ground and air-air Digital Link (VDL) Mode 4 radio equipment; Technical characteristics and methods of measurement for aeronautical mobile (airborne) equipment; Part 4: Point-to-point functions (V1.3.1)
Introduction The present document states the technical specifications for Very High Frequency (VHF) Digital Link (VDL) Mode 4 aeronautical mobile (airborne) radio transmitters@ transceivers and receivers for air-ground and air-air communications operating in the VHF band@ using Gaussian Filtered Frequency Shift Keying (GFSK) modulation with 25 kHz channel spacing and capable of tuning to any of the 25 kHz channels from 112@000 MHz to 136@975 MHz as defined in ICAO VDL SARPs [2]. The present document may be used to produce tests for the assessment of the performance of the equipment. The performance of the equipment submitted for type testing should be representative of the performance of the corresponding production model. The present document has been written on the assumption that: the type test measurements will be performed only once@ in an accredited test laboratory and the measurements accepted by the various authorities in order to grant type approval; if equipment available on the market is required to be checked it will be tested in accordance with the methods of measurement specified in the present document or a documented alternative approved by the certifying authority; equipment comply with ETSI EN 302 842-1 [5] and ETSI EN 302 842-2 [6]. NOTE: The present document has been produced with a view to maintaining consistency of numbering with the equivalent standard for ground equipment (ETSI EN 301 842 [i.1]). Where requirements are the same@ they have been given the same number. Some new airborne requirements have been inserted between requirements that were sequential in ETSI EN 301 842 [i.1]. This has led to a non-standard form of numbering for new requirements in some places.