June 18, 2006
June 18, 2006
June 21, 2006
Computers in Education
11.1434.1 - 11.1434.8
Communication Systems Toolkit As a Tool for Innovation
In previous publications, we have discussed the preparation1, the utilization2 and the effectiveness3 of a Virtual Toolkit for Communication Systems, which takes advantage of LabVIEW’s graphical user interface. This paper describes the use of the same toolkit in a class project that demonstrates a novel idea for envelope detection of amplitude modulated (AM) signals. It first proposes a new technique of envelope detection using sampling. It then presents a mathematical model and analysis to show the feasibility of this new technique. Finally, the results of a simulation of the proposed technique using the toolkit will be presented followed by a discussion of the evolution of the toolkit from a demo package to a research tool.
This paper is a follow-up on recent papers that describe a simulation toolkit for communication systems based on LabVIEW1,2 and its reception by students at two different institutions3. In those papers we stated that in the absence of hardware that would reinforce the theoretical presentation, computer simulations of the systems described in class are the next available tools to bring these concepts to life. Those papers also describe the particular class environment and the process in which the software development tool, namely LabVIEW, was chosen. Although MATLAB is the standard software tool employed in the areas of signals and systems, as evidenced by the proliferation of books4-6 devoted to MATLAB based exercises in those subjects, the choice of the software tool is justified in other publications1, 7, 8.
This paper will describe the use of the toolkit in the demonstration of a novel idea for envelope detection of AM signals. Section II will provide a summary of amplitude modulation and envelope detection of AM signals as well as recent developments in envelope detection and related fields. Section III will present the method of sampling the AM signal for envelope detection, present a mathematical analysis of the proposed process and demonstrate the feasibility of this method with the toolkit. Section IV will conclude with a discussion of the toolkit as well as comments on hardware implementation.
II. Envelope Detection of AM Signals
An AM signal, s(t), is given by
s(t) = Ac [1+ m(t)]cos ω c t (1)
where m(t) is the modulating (or message) signal, Ac and ωc are amplitude and frequency of the carrier (modulated) signal respectively9. Figure 1 shows the front panel of the virtual instrument that demonstrates AM with the toolkit. The upper left graph is that of a square wave message signal and the upper right graph depicts its magnitude spectrum. The lower left graph is that of
Tanyel, M. (2006, June), Virtual Toolkit For Communication Systems As A Tool For Innovation Paper presented at 2006 Annual Conference & Exposition, Chicago, Illinois. 10.18260/1-2--462
ASEE holds the copyright on this document. It may be read by the public free of charge. Authors may archive their work on personal websites or in institutional repositories with the following citation: © 2006 American Society for Engineering Education. Other scholars may excerpt or quote from these materials with the same citation. When excerpting or quoting from Conference Proceedings, authors should, in addition to noting the ASEE copyright, list all the original authors and their institutions and name the host city of the conference. - Last updated April 1, 2015