直接调制技术 meaning in English

direct modulationtechnique
dmt direct modulation technique

In this paper , direct modulation technology working at microwave band is researched
本文研究的是微波波段的直接调制技术。
The carrier wave is modulated directly by the baseband signal at several frequency point in l band and s band . firstly , this paper clarifies the theory of i / q modulation , elaborates evm and acpl , and analyzes the effect of amplitude and phase unbalance and dc offset on evm . secondly we review the basic principle of phase locked loop and it ’ s composing parts , including the basic conception and design method of pll frequency synthesizer , especially introduce the charge pump pll frequency synthesizer in detail
首先,在阐述i / q正交调制基本原理的基础上,通过对误差矢量和邻近信道功率泄漏的详细分析,定性、定量地讨论了各种非理想电路因素(如相位不平衡、幅度不平衡、直流偏差等)对调制器性能的影响;其次,介绍了锁相环的工作原理和基本组成部分,包括锁相环的设计和环路滤波器的设计,特别详述了电荷泵锁相频率源;第三,介绍了采用直接调制技术模拟卫星信号的射频前端的设计;最后,对整个直接射频调制系统进行测试,结果基本上达到了课题要求。