摘要
在QAM接收机中多采用相干解调,这需要接收端提供一个与发射端同频同相的相干载波,但是完全同频同相载波信号的产生是有一定难度的。针对此,笔者详细介绍了16QAM差分调制解调的原理,并通过接收端解码电路相应的运算规则消除了频偏和相偏的影响,免除了复杂的载波和相位同步,降低了QAM接收机的复杂度。在DSP实现中,采用了取整映射法,把浮点运算转化为定点运算,减少了计算量。
Quadrature amplitude modulation（QAM） is one of modulations with high spectrum usage, and used widely in modern communication. Most of the QAM receivers adopt coherent demodulation, and the coherent carrier signal generated by the receiver should have the same frequency and phase with the received signal, but it＇s difficult to generate such a carrier signal. Therefore, this paper introduces the principle of 16QAM and differential modulation and demodulation in detail. Through the detecting algorithm in the receiver, the effect of frequency and phase deviation is eliminated effectively,and it makes the QAM receiver easy to realize. In DSP realization a method of integer mapping is adopted , it＇s favorable to transform float-point operation to fixed-point operation, and reduce the total operational load.
出处
《太原理工大学学报》
CAS
北大核心
2008年第5期464-466,478,共4页
Journal of Taiyuan University of Technology
基金
电子科技大学通信抗干扰技术国家级重点实验开放基金资助项目(HG2006027)
