Bandwidth Efficient Aeronautical Telemetry Modem and Transceiver Research

摘要

In RF power and spectral efficient digital communication systems, the transmitted signals are required to have both narrow-band spectrum and constant envelope. To meet these requirements, it is desirable to use spectrally efficient modulation techniques. FQPSK 1-2 and 16-state Superposed QAM (16-SQAM 1, 3, also called FQAM) have been demonstrated to achieve higher power and spectral efficiency, and also show good error probabilities in NLA and Additive White Gaussian Noise (AWGN) channels. These signals contain 'offset' property in quadrature (Q) channel 1 relative to in-phase (I) channel, which prevents the envelopes of the modulated signals from crossing zeros and allows to achieve higher power efficiency 2.