LABVIEW-BASED LABORATORY ENVIRONMENT FOR LEARNING OF FILTERING CONCEPTS R. Krneta,Đ. Damnjanović and M. Đoković Technical faculty, Čačak, Serbia Technical faculty, Čačak, Serbia rkrneta@gmail.com , fic177@hotmail.com , marina_djokovic87@yahoo.com Abstract—Better understanding of the acquired theoretical knowledge in the field of digital signal processing, for their successful use in future engineering practice, is achieved by introducing interactive laboratory experiments in the classroom. In this paper we present realization of LabVIEW virtual interactive DSP experiments and hardware DSP laboratory experiments on the NI-ELVIS II + development platform. These experiments can be used in the DSP lab for "visualization" of filtering concepts. For the purpose of “visualization”, LabVIEW filter palette has been used for the procedure of band pass digital filter design and active band pass filter has been realized on the NI-ELVIS II+ developing platform. Theoretical characteristics of active band pass filter validated by measurements on realized hardware model. Keywords – band pass filter, filter characteristics, virtual experiments, hardware development platform, visualization of DSP theory I. INTRODUCTION As a rule, learning basic theoretical concepts of signal and system analysis and synthesis is difficult for the students of engineering. This difficulty is a result of the gap between understanding mathematical formalisms of these concepts and student’s abilities to connect these theoretical concepts with practical engineering applications. In the aim of solving this problem many “recipes” suggest “visualization” of digital signal processing theory [1]. MATLAB software package has become standardized and inevitable way of “visualization” of DSP theory for a long time. Many MATLAB based DSP “visual experiments” are constituent parts of lectures and practical exercises at the courses of system and signal theory and digital signal processing [2], [3], [4]. Ability of programming in MATLAB is the skill which is acquired by students at the beginning of their Electrical Engineering studies. However, all that can be done with MATLAB based DSP “virtual experiments”, in simpler way, without writing lines of program code, and it can also be done with using software package LabVIEW(Laboratory Virtual Instrument Engineering Workbench).LabVIEW is graphic developing environment with built-in functionality for simulation, data acquisition, instrumentation, measurement analysis and data presenting. User’s interface for some application is created without any code line, with simple “drag-and- drop” of pre-defined objects [5]. Graphic applications created in LabVIEW are called virtual instruments (VI), as their look and functions “imitate” real instruments: oscilloscopes, voltmeters, ammeters, function generators, etc. [6]. LabVIEW contains a great number of library functions which are used for creating applications for solving set of standard tasks from the field of digital signal processing, such as: DFT and FFT transform, presentation and analysis of signals in spectral and time domain, analogue and digital FIR and IIR filters, multirate filters, etc. LabVIEW filter palette possesses range of tools for synthesis and analysis of filters [5] (Fig.1). Figure 1. LabVIEW filter palette However, virtual laboratory environment of MATLAB and LabVIEW cannot completely prepare students of Electrical Engineering for work with hardware equipment and real instruments needed for designing, testing and running of practical engineering applications. So, experiments with hardware equipment and real instruments are necessary at studies. The aim of hardware laboratory experiments in education of engineers through “physical contact with hardware” also means better understanding of acquired theoretical knowledge in order to apply it more successfully in future engineering practice. Hardware lab experiments for “visualization” of DSP theory is possible to realize even without a laboratory which often demands expensive hardware for – 451 – 6th IEEE International Symposium on Applied Computational Intelligence and Informatics • May 19–21, 2011 • Timişoara, Romania 978-1-4244-9107-0/11/$26.00 ©2011 IEEE