Symbol Judgment in Digital AM Broadcasting System Based on Hybrid Modulation
Abstract: Many advantages can be achieved by using AM-MPPSK hybrid modulation in digital AM broad-casting system. This paper describes the MPPSK scheme principle and basic judgment method in hybrid modulation, on which some improvements are made. Dynamic threshold method is pro-posed to make up for lack of the fixed threshold discrimination, to insure the best demodulation performance. Dynamic threshold method requiring the demodulator to perform channel estimation is more complicated. Thus, an improved MPPSK modulation is introduced, and its principle and symbol decision are described. By this improvement, the impact magnitude appears in any symbol period, which avoids the need for amplitude judge to distinguish zero and non-zero symbols. Theory and experiments have proven that better demodulation performance can be obtained. Partial dual symbol joint discrimination is introduced to solve the platform of bit error ratio at high signal to noise ratio. The simulation results show that the partial dual symbol joint discrimination makes a more reliable judgment by effectively utilizing the previous symbol judge results.
文章引用: 朱超越 , 吴乐南 , 李旭森 (2015) 基于复合调制的数字AM广播系统中的码元判决方法。 无线通信， 5， 51-59. doi: 10.12677/HJWC.2015.51008
 National Association of Broadcasters (2011) In-band/on-channel Digital Radio Broadcasting Standard.
 European Telecommunications Standards Institute (2012) Digital Radio Mondiale (DRM) System Specification.
 Zhang, S.K. and Wu, L.N. (2009) Hybrid modulation based on combining of AM and UNB. Journal of Convergence Information Technology (JCIT), 4, 77-81.
 戚晨皓, 吴乐南, 张仕元 (2007) 基于复合调制方式的AM广播. 应用科学学报, 5, 451- 455.
 逄军 (2014) 兼容调幅广播体制的复合调制. 东南大学信息科学与工程学院, 南京.
 王继武 (2012) 基于冲击滤波的EBPSK解调器设计、优化与应用. 硕士学位论文, 东南大学信息科学与工程学院, 南京.
 王伟 (2013) 基于调幅广播体制的复合调制技术研究. 硕士学位论文, 东南大学信息科学与工程学院, 南京.
 普罗科斯, 著, 张力军, 译 (2011) 数字通信. 第五版, 电子工业出版社, 北京.