基于CORDIC算法的数字中频检波技术研究

为了解决模拟包络检波器受温度影响大、测试精度不高且丢失相位信息等问题,提出了一种基于CORDIC算法的数字中频检波方案,完成幅度、相位及频率检测功能.首先讨论了数字检波的工作原理,分析了其数学模型,然后给出了基于CORDIC算法的幅度和相位检测方案,并在数字鉴相基础上,介绍了使用一阶差分结构实现数字鉴频的方法,同时分析了差分鉴频中出现的相位模糊问题,给出了如何提高鉴频精度的方法.最后,使用FPGA实现了基于CORDIC算法的数字检波器.通过计算机仿真和应用实例表明,基于CORDIC算法的数字中频检波方案是可行的,并且可以获得较高的测量精度.

Research of Digital IF Detector Technology Based on CORDIC Algorithm

To solve the problem with analog detector of temperature sensitivity,low precision and phase losing,a digital IF detector technique based on CORDIC algorithm to measure amplitude,phase and frequency is presented.Firstly,the theory of digital detection and the analysis of mathematic model are discussed.Secondly,the amplitude and phase detection scheme based on CORDIC algorithm is proposed.On the basis of digital phase discriminating,the digital frequency discrimination method by the structure of differential frequency discrimination is introduced.At the same time,the phase blur problem in differential frequency discrimination is analyzed while the method on how to improve precision of frequency discriminating is given.Finally,the digital detector based on CORDIC algorithm is successfully implemented by FPGA.The computer simulation and experimental results show that digital IF detector based on CORDIC algorithm is feasible and can reach high resolution.