基于FPGA的便携式选频向量仪设计

发布时间：2018-05-21 20:43

本文选题：选频向量仪 + 现场可编程门阵列　；参考：《哈尔滨理工大学》2016年硕士论文

【摘要】：向量测量技术广泛应用于科学研究和工程应用等诸多领域。例如,在铁路移频轨道测量中,在通信、现代医学及军事国防领域中,向量测量都起着不可替代的作用。而工程技术中不仅需要对单一频率的信号进行幅度、频率及相位差的测量,通常要在多种混合频率的信号中选出某特定频率的信号并对其进行测量。此外,很多情况下需要仪器在野外作业,因此对向量测量仪器的体积、功耗、操作的灵活性等提出了较高要求。而当今用于向量测量的仪器很难同时满足这些需求。本设计利用差频变换技术和开关乘法原理,设计了一款精确测量信号的相位差、幅度和频率的便携式选频向量仪,该设计克服了传统仪器功能单一的缺点,为系统设计了点频、选频、扫频及移频四种工作模式来满足不同的测量需求。针对野外作业中对测量结果动态监测的需求,将该设计做成便携式的、操作界面友好又兼具联网功能的仪器。人机交互界面使用TFT触摸屏,同时为该仪器设计了基于USB模块和基于WIFI模块的两种通讯方式,这样能将测量结果实时的传输到上位机,方便了对测量结果进行动态监测及分析。在进行幅度和相位差测量时,为了提高测量频带宽度、降低幅度参数测量时幅频特性的影响以及对脉冲控制信号频率分辨率的要求,本设计采用两级差频变换的方法对测量过程进行了优化。根据被测信号的频率范围,通过软件编程控制模拟开关,使之选择直接测量、通过一级差频变换法测量或者通过两级差频变换法来测量幅度和相位差。本设计提出了一种基于FPGA中数字锁相环的脉冲信号源的设计方案。通过算法分析及Matlab仿真,计算出了产生不同频段的脉冲信号的频率分辨率,对信号源的设计提供了参考。并且该设计实现了低成本、低功耗。该便携式选频向量仪采用Cyclone IV系列芯片EP4CE15F17C8N作为主控制器,通过构建Nios II软核,来对外围电路进行控制。通过软件编程,实现了根据测量需求在四种工作模式之间的灵活切换。人机交互采用Nios II上移植uC/OS II及ucGUI的方式来呈现测量结果及输入控制命令。该仪器能达到如下指标:频率测量范围是10Hz~10MHz,频率的分辨力是0.1 Hz;幅度测量范围是10mV~100V,准确度为1%;相位测量范围是0.0°~359.9°,分辨力为0.1°。
[Abstract]:Vector measurement technology is widely used in many fields, such as scientific research and engineering applications. For example, vector measurement plays an irreplaceable role in railway frequency shift orbit measurement, communication, modern medicine and military defense. In engineering technology, it is not only necessary to measure the amplitude, frequency and phase difference of a single frequency signal, but also to select and measure a certain frequency signal from a variety of mixed frequency signals. In addition, in many cases, instruments are required to operate in the field, so the volume, power consumption and flexibility of the vector measurement instruments are required. The instruments used for vector measurement today are difficult to meet these needs at the same time. In this design, a portable frequency vector meter is designed to accurately measure the phase difference, amplitude and frequency of the signal by using the technology of differential frequency conversion and the principle of switching multiplication. The design overcomes the shortcoming of single function of the traditional instrument and designs the point frequency for the system. Select frequency, sweep frequency and shift frequency four working modes to meet different measurement requirements. In order to meet the requirement of dynamic monitoring of measurement results in field work, the design is made into a portable instrument with friendly operation interface and networking function. The man-machine interface uses TFT touch screen, and two communication modes based on USB module and WIFI module are designed for the instrument, which can transmit the measurement results to the host computer in real time, and facilitate the dynamic monitoring and analysis of the measurement results. When measuring amplitude and phase difference, in order to increase the bandwidth of measurement, reduce the influence of amplitude-frequency characteristic when amplitude parameter is measured, and request the frequency resolution of pulse control signal, This design adopts the method of two-stage difference frequency transform to optimize the measurement process. According to the frequency range of the measured signal, the analog switch is controlled by software programming to make it choose to measure directly, the amplitude and phase difference are measured by the method of one-stage difference frequency transformation or by two-stage difference frequency transform. This paper presents a design scheme of pulse signal source based on digital phase-locked loop (DPLL) in FPGA. Through the algorithm analysis and Matlab simulation, the frequency resolution of the pulse signal with different frequency bands is calculated, which provides a reference for the design of the signal source. And this design realizes low cost and low power consumption. The portable frequency selective vector meter uses Cyclone IV series chip EP4CE15F17C8N as the main controller, and controls the peripheral circuit by constructing the Nios II soft core. Through software programming, the flexible switching between the four working modes is realized according to the measurement requirements. UC/OS II and ucGUI are transplanted on Nios II to display the measurement results and input control commands. The instrument can reach the following targets: the range of frequency measurement is 10 Hz, the resolution of frequency is 0.1 Hz, the range of amplitude measurement is 10 MV / 100 V, the accuracy is 1 and the range of phase measurement is 0.0 掳/ 359.9 掳and the resolution is 0.1 掳.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN791;TM935

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