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基于LABVIEW的信号频谱分析仪设计
摘要
随着科学技术的进步，对测量技术的要求越来越高。电子测量技术在各个领域得到越来越广泛的应用，传统的电子测量仪器由于其功能单一，体积庞大，已经很难满足实际工作的需要。集成电路和计算机技术的迅猛发展使电子测量仪器逐渐向数字化、智能化方向发展，与传统仪器相比表现为：功能更强、处理速度更快、频带更宽、用途更广、操作更简单、体积更小、可扩充性更好。微型计算机的普及程度和性能不断提高，使得基于PC平台的虚拟仪器系统应运而生。虚拟仪器可以充分利用计算机的运算、存储和显示功能，因而在降低仪器成本的同时使仪器的灵活性和数据处理能力大大提高，可以很好地满足学校科研和教学改革的需要。
本文论述了基于虚拟仪器概念的信号采集系统的实现方案，重点讨论了在数据传输、显示和处理中的关键技术。使用USB数据采集卡，最终实现了基于 PC 平台的，具有频率计和频谱分析仪功能的数字存储示波器系统。本文所选用的软件 LabView 是美国 NI 公司的创新软件产品，也是日前应用最广泛、发展最快、功能最强的图形化软件开发环境。它具有开发周期短、运行速度快、可重用性、使用方便灵活等优点。因此LabView 对虚拟存储示波器的设计是一种最理想的方法。
关键词：虚拟仪器；数字存储示波器；谐波分析仪；LabView仪器驱动程序
THE DESIGN OF SIGNAL SPECTRUM ANALYSER
BASED ON LABVIEW
基于LABVIEW的信号频谱分析仪设计
ABSTRACT
With the advancement of science and technology, the development of measurement technique is getting more and more important. The application of electronic measurement technique has extended to more fields than ever. Due to limited functions and big size, traditional electronic measurement equipment is no longer suited for common purposes. Thanks to the rapid development of integrated circuit and computer technology, measurement instruments are becoming digitized and intelligentized.Compared with traditional equipment, the new instruments have more functions, higher processing speed, wider bandwidth, friendlier interface,smaller size and better expandability. The prevalence and rocketing development of personal computers give birth to a new kind of instrument, Virtual Instrument (VI). VI is based on PC platform, and can make use of the software and hardware resources of a PC. Compared with its ability of data processing and flexibility, VI has a low price, which means it is a good choice for research and teaching reform inuniversities.
This dissertation discusses the implementation of a signal acquisition system,based on the concept of VI and focuses on key techniques in data transmission, display and processing. With a USB data acquisition card connectedto PC, a digital storage oscillograph (DSO) with the function of cymometer and spectrum analyzer is developed.LabVIEW is the innovate software of national instruments corps, of America.lt is also the most widely used、the most quickly developing and the strongest function gragh software.lt has short epolder and fast run-rate.So LabView is the best way of design virtual digital storage oscillogragh.
Key words: virtual instrument；digital-storage oscillograph；Harmonic-Analyser
LabVIEW-instrument driver equivalent
基于LABVIEW的信号频谱分析仪设计
目录
1 绪论.................................................................................................................................................... 1 1.1 虚拟仪器的概念 ................................................................................................................... 1 1.2 虚拟仪器的组成 ................................................................................................................... 1 1.3 虚拟仪器的特点及优势 ..................................................................................................... 2 1.4虚拟仪器的发展状况 .......................................................................................................... 3 1.5 本课题的意义 ........................................................................................................................ 3 2 数据采集和谐波分析理论 ......................................................................................................... 6 2.1 数据采集理论基础 .............................................................................................................. 6 2.1.1 快速傅立叶变换(FFT) ............................................................................................... 7 2.1.2 准同步采样 .................................................................................................................... 9 2.2 谐波分析理论 ...................................................................................................................... 11 2.2.1 谐波分析原理 ............................................................................................................. 11 2.2.2 谐波参数定义 ............................................................................................................. 13 2.2.3 功率概念 ....................................................................................................................... 14 3 系统软硬件开发平台 ................................................................................................................ 15 3.1 系统软件开发平台-LABVIEW ......................................................................................... 15 3.2 系统硬件平台 ...................................................................................................................... 16 4系统软件体系结构 ...................................................................................................................... 19 4.1 软件总体构成 ...................................................................................................................... 19 4.2 数据采集过程 ...................................................................................................................... 21 4.3 系统应用程序设计 ............................................................................................................ 22 5 仿真结果和误差分析 ................................................................................................................ 30 5.1 仿真结果................................................................................................................................ 30 5.2 误差分析................................................................................................................................ 34