多元位置相移键控(MPPSK)是一种新型单载波调制技术。为提高解调性能,采用窄带滤波器提取相干载波对MPPSK信号的冲击滤波输出进行相干检波,得到信号包络;根据包络信号与本地模板序列的相关性,联合幅度一位置检测法和相关函数检测法,设计出相干相关解调器;基于Matlab仿真对传统的幅度门限解调器和相干相关解调器的性能进行了对比。结果表明,在强噪声环境下两者性能趋于一致;在弱噪声环境下,相干相关解调器提升了系统解调性能且简化了相干接收机结构。分析和实验表明了所提MPPSK解调器的有效性。
M-ary position phase shift keying (MPPSK) is a new mono-carrier modulation. To improve MPPSK demodulations, a coherent-correlation scheme is proposed. This scheme uses a coherent carrier extracted by a narrowband filter to coherently detect the envelope of the response of a special impacting filter to MPPSK modulated signals. According to the correlation between the envelope and a local template sequence, a coherent-correlation demodulator is brought forward by jointing the amplitude-position and correlation detection methods. The traditional amplitude threshold demodulator and the proposed demodulator are simulated and compared on the Matlab platform. Results show that the performance approximates the same in strong noise, while the new one performs better along with a simplified coherent receiver structure, which demonstrates the validity of the new demodulator.