摘要
本文对多电平QAM数字微波系统中载波恢复方法之一的导频插入法进行了一全面研究。从能抑制基带信号低频分量的反馈平衡编码入手,导出经反馈平衡编码后的信号功率谱;导出插入导频分量的大小与信号平均功率衰减程度的关系和采用导频插入法的MQAM系统误码率计算公式;分析了信道多径衰落、剩余的信号低频分量对导频的干扰作用;给出了采用导频插入法的MQAM系统性能计算机模拟结果。理论估算和计算机模拟结果均表明,在MQAM系统中,用导频插入载波恢复法能取得较满意的效果,在许多方面,特别是M值很大的情况,优于环路载波恢复法。
One of the carrier recovery methods for MQAM digital microwave radios——a pilot carrierinjection method is discussed fully.The following items are studied theoretically. (1) The power spectrum of a data sequence which the DC and low-frequeny components existing in it are suppresed by coding technique. (2) Signal-to-noise ratio penalty caused by injecting a pilot. (3) Error probability performance of a pilot carrier injected MQAM system. (4) Carrier-to-noise ratio impairment caused by the effect of multipath fading and the lower-frequency component remained in the baseband data sequences.Performance of a pilot carrier injected MQAM system is investigated with computer simulation The results of theoretically estimated and computer simulation show that the pilot carrier injection method provides significant advantages compared with those carrier recovery loops
出处
《通信学报》
EI
CSCD
北大核心
1991年第2期26-33,42,共9页
Journal on Communications
