Aviation quadrature phase shift keying
|Term||aviation quadrature phase shift keying|
The particular form of offset quaternary phase shift keyed modulation which is used in AMSS for channel rates greater than 2 400 bits/s. A-QPSK is a modulation technique which maps a 'O' into a 0 degrees and '1' into 180 degrees, or '0' into 90 degrees and '1' into 270 degrees, alternating between the two options on successive bits. The encoded A-QPSK data stream is then filtered such that the modulated spectrum meets the amplitude mask of Table A1-3 and the phase mask defined in Table A1-2 in appendix 1 to Chapter 4 [of Annex 10/III].
ICAO, Official definition, ANNEX 10/III Aeronautical Telecommunications — Part I, Digital Data Communication Systems; Part II, Voice Communications Systems