A Novel High-speed NLA-16SQAM modulation module

摘要

This paper introduces a novel NLA-16SQAM modulation module that can transmit satellite data in X band at a bits rate of 600Mbps. Different from the conventional QAM, NLA-16SQAM signals are generated by combining , two SQPSK signals. First, a serial data stream is split into four parallel streams that form two in-phase and quadrature phase signal pairs. Then let quadrature phase digit signals lag behind the in-phase signals by one half symbol. Each pair of signals are converted from absolute codes into relative codes, and then sent into a SQPSK modulator. Two SQPSK output signals are amplified by their own saturated power amplifier, which produce a 6 dB difference in their voltage levels, and then sent into a power synthesizer to obtain NLA-16QAM signals. Not only can the NLA-16SQAM modulation module improve the spectral efficiency, but also make the best of precious energy on satellites.