下调制 meaning in English

downward modulation

The content of this dissertation include : orthogonal transformation of digital signal ; mathematic model of modulation signals and software - defined radio receiver ; nine feature parameters of the modulation algorithm and threshold of feature parameter ; development procedure of modulation recognition by ccs and the modulation digital signals produced through matlab ; discussion on sampling speed and instantaneous frequency and analysis of experiment " s result
本文给出了在ccs集成开发环境下调制识别算法仿真实现的程序设计和利用matlab仿真产生调制信号的方法；分析了调制识别算法的仿真实验结果；对采样速率的选取、非弱信号段判决、瞬时频率的计算以及算法数据关联性的简化等方面进行了研究。