The Development Of Remote Experiment About"PLL Frequency Modulation&Demodulation Circuits" Based On LabVIEW

With the development of measuring instrument, which is going into more digital, virtualinstrument has rose its fame and begun to replace the traditional instrument gradually. Applyvirtual instrument in the experiment can not only save investment in actual instruments, but alsoreduce the time of learning maintenance. Furthermore, the virtual instrument will appeal studentsto practice more, which in turn results in a better learn of relevant knowledge for users. Due to thehigh cost, complicate structures, low liquidity of the traditional instrument, the new instrumentwhich can be widely accepted under a variety of circumstance will be better used in education andalso save experiment cost.The software devised by American company called NI (National Instruments) can integratethe illustrative diagram and industrial standardized SPICE simulation into one environment, whichwill make the circuit easy to analyze. NI ELVIS II+is the design platform based on graphical codecalled LabVIEW, and it successfully integrates12types of popular specific instruments such asoscilloscope, digital multimeter, function generator, etc. This virtual instrument design platformwhich is based on ELVIS and LabVIEW realizes a variety of applications including education,simulation design, circuit board build, ELVIS platform test, LabVIEW function process and USBinterface. Moreover, this kind of platform has the ability in providing the flexibility of the virtualinstrument and extracting the data conveniently. The beginning part of this project completed thecircuit simulation and optimize the parameter with the assistance of Multisim, then applied ELVISto complete hardware design, function test and united simulation of the whole system, finallyemployed LabVIEW to devise the platform.This project is focused on the design of NE564simulation. For this topic, it first introducedthe basic structure of frequency modulation&demodulation and the operation principle ofPLL frequency modulation&demodulation based on NE564, analyzed NE564by chip modelbuild under Multisim, brought in SPICE model, and validated the correctness of internal model bytesting the external circuit.Then this paper showed the whole process about how to devise theillustrative diagram of PLL frequency modulation&demodulation circuit, analyze the Multisimsimulation and in the end successfully realize the simulation of PLL frequency modulation& demodulation in Multisim.The final part of this project introduced the result of this design, whichis a complete remote experiment control platform. With this platform, one can transfer the virtualinstrument in LabVIEW, collect the data from Elvis platform and finally show the whole PLLfrequency modulation&demodulation remote control platform on the screen of PC. Meanwhile,the final part showed the code for PLL frequency modulation&demodulation based on thecombination of LabVIEW, Multisim and DAQmx. This code is mainly composed by five partsincluding introduction module, parameter module, simulation module, spectrum analyzer moduleand oscilloscope module. At last, this paper presented the process and functions of these modulesand successfully applied them in LabVIEW to test and analyze the circuit.The research findings of this project make a solid basis for the application of remoteexperiment with virtual instrument.