虚实融合的混频电路远程实验平台设计与实现

发布时间：2018-04-21 02:04

本文选题：虚拟仪器 + LabVIEW　；参考：《东华大学》2017年硕士论文

【摘要】：目前,在对人才的培养中,实践教学所占的比重正日益提高,实验是理论与实践结合的桥梁,也是高等院校工科教学的重要环节,但是目前通信电路教学中普遍存在的问题是理论教学与实践教学分离,完成课程理论学习之后进实验室,实验对象是固化的实验箱,只能对少部分电路元件进行改变以此来观察电路性能的变化。因此构建一个突破传统局限的虚拟仿真实验与实际硬件实验相结合的网络化实验室已成为需要解决的重要课题。论文借助于NI公司的Multisim电路仿真软件、基于图形化编程的LabVIEW软件和ELVIS平台,将电路的仿真设计、硬件实现及电路性能测试分析紧密融合,构建了基于LabVIEW虚拟仪器的集成化混频电路远程实验平台。论文设计与开发的虚实融合远程实验平台,以模拟乘法器MC1496构建的混频电路以及三极管混频电路为主要研究对象,首先结合混频原理和电路的相关知识,在Multisim仿真软件中进行芯片仿真模型的建立及混频电路的设计,并对电路进行了直流工作点分析、傅里叶分析、混频增益与1d B压缩电平分析、本振信号幅值影响分析、选频网络分析、混频干扰与失真分析和噪声特性仿真分析,深入研究了电路不同参数对混频特性的影响,得到元件参数值的最佳取值范围。其次根据完成仿真优化的电路,设计硬件电路PCB板,包括两种混频电路的设计、运用继电器实现硬件电路切换的设计以及与ELVIS平台通信接口的设计,完成了混频电路PCB板的硬件制作及元器件的焊接工作。然后利用ELVIS平台集成的虚拟仪器进行硬件电路的控制与测试,验证仿真结果的准确性和有效性。最终通过LabVIEW编程开发出一个完整的混频电路远程控制实验平台。详细介绍了基于LabVIEW的实验分析界面设计及程序设计,并通过WEB发布技术,实现实验平台的远程操作访问。开发的远程实验平台可以在界面中选择实验训练内容,包括混频原理介绍模块、硬件参数配置模块、联合仿真模块、频谱仪与示波器测试模块。平台不仅能够将LabVIEW与Multisim结合,完成对Multisim仿真数据的采集、测量、存储与显示,通过在界面中调整输入控制参数,动态显示电路性能变化,实现了自动化仿真分析实验。同时,也可以与ELVIS平台结合,将ELVIS的虚拟仪器集成在实验平台中,实现对原型PCB电路的控制与性能测试,构建了一个虚实融合的混频电路远程控制实验平台。测试结果表明,该平台性能稳定,使用方便,能够有效缓解学生人数众多与现有实验室仪器设备匮乏之间的矛盾,突破时间和空间限制,为学生提供随时随地的实验电路分析及测试训练,为实现验证性实验向设计性实验跨越奠定基础,具有一定的实用价值。
[Abstract]:At present, in the training of talents, the proportion of practical teaching is increasing day by day. Experiment is a bridge between theory and practice, and it is also an important link in engineering teaching in colleges and universities. But at present, the common problem in communication circuit teaching is the separation of theory teaching and practice teaching, and the experiment object is the solidified experimental box after completing the course theory study. Only a small number of circuit components can be changed to observe the performance of the circuit. Therefore, it has become an important task to construct a networked laboratory which can break through the traditional limitations of virtual simulation experiment and actual hardware experiment. With the aid of NI company's Multisim circuit simulation software, based on LabVIEW software and ELVIS platform of graphic programming, the circuit simulation design, hardware implementation and circuit performance test and analysis are closely integrated. The remote experiment platform of integrated mixing circuit based on LabVIEW virtual instrument is constructed. The virtual and real fusion remote experimental platform is designed and developed in this paper. The mixing circuit constructed by analog multiplier MC1496 and the transistor mixer circuit are taken as the main research objects. Firstly, the mixing principle and the related knowledge of the circuit are combined. In the Multisim simulation software, the chip simulation model is built and the mixer circuit is designed. The DC operating point analysis, Fourier analysis, mixing gain and 1dB compression level analysis, the influence analysis of the amplitude of local oscillator signal are carried out. The influence of different circuit parameters on the frequency mixing characteristics is deeply studied and the optimum range of component parameters is obtained by analyzing the frequency selection network, mixing interference and distortion, and simulating the noise characteristics. Secondly, according to the circuit that completes the simulation optimization, the PCB board of hardware circuit is designed, including the design of two kinds of mixed-frequency circuit, the design of hardware circuit switch by using relay and the design of communication interface with ELVIS platform. The hardware of the PCB board and the welding of the components are finished. Then the hardware circuit is controlled and tested by the virtual instrument integrated on ELVIS platform to verify the accuracy and validity of the simulation results. Finally, a complete remote control experiment platform of mixing circuit is developed by LabVIEW programming. The design and program design of experimental analysis interface based on LabVIEW are introduced in detail, and the remote operation access of experimental platform is realized by WEB publishing technology. The remote experimental platform can select the experimental training contents in the interface, including the introduction module of mixing principle, the hardware parameter configuration module, the joint simulation module, the spectrometer and the oscilloscope test module. The platform can not only combine LabVIEW and Multisim to complete the acquisition, measurement, storage and display of Multisim simulation data, but also realize the automatic simulation analysis experiment by adjusting the input control parameters in the interface and dynamically displaying the performance changes of the circuit. At the same time, the virtual instrument of ELVIS can be integrated with the ELVIS platform to realize the control and performance test of the prototype PCB circuit. A virtual and real mixing circuit remote control experimental platform is constructed. The test results show that the platform is stable in performance and easy to use. It can effectively alleviate the contradiction between the large number of students and the lack of existing laboratory instruments and equipment, and break through the time and space constraints. It can provide students with experimental circuit analysis and test training at any time and anywhere, and lay a foundation for realizing the leapfrogging from confirmatory experiment to design experiment, which has certain practical value.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN70;TP311.52

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