EVM可控的数字调制信号的产生方法研究

针对数字信号发生器检定装置和信号分析仪期间核查缺乏产生EVM值可控的数字信号标准装置的情况,在理论推导加性高斯白噪声环境下的EVM与SNR之间的解析关系基础上,提出了基于噪声发生器和数字信号发生器的EVM值可设置的数字调制信号产生系统方案。对系统输出的BPSK信号和64QAM信号展开重复性和稳定性测试,测试结果表明,尽管理论设置值与实际值之间存在一定的差距,但并不影响任意EVM值数字调制信号产生系统的稳定输出,其重复性和稳定完全可满足数字信号发生器校准装置或者矢量信号分析仪的期间核查的需要。

Research on Generation of Digital Modulation Signals with EVM Controllable

To solve lacking of device which can cover the EVM range of digital signals in the intermediate checks of calibration equipment of digital signal generator and signal analyzer, an analytical relation between SNR and EVM was derived. A system based on noise generator and digital signal generator was proposed which can generate digtal modulation signals with any EVM value. To verify the repeatability and stability of the output of the system, experiments were performed, BPSK and 64QAM signals were tested, and results showed that even though the values between the theory and the measured were not the same, the output of the sytem was very stable, the repeatability and stability of the output qualified with needs of the intermediate checks of calibration equipment of digital signal generator and signal analyzer.