 
Exploring Fourier Transform Techniques with Mathcad©  
Mark Iannone Department of Chemistry Millersville University Millersville, PA 17551 USA mail to: miannone@marauder.millersv.edu  
Abstract  
These four Mathcad documents illustrate different aspects of the Fourier transform. They explore the source of the Nyquist frequency and the dependence of the resolution of the spectrum on sampling. In FTIntro.mcd, students achieve a qualitative understanding of the Fourier transform through experimentation with graphic representations of data and their transforms. In Part 1 of FTIntro.mcd, students sample a continuous function and learn how aliasing can occur; in Part 2, a vector of a more complex waveform illustrates that the frequencies contained in the waveform appear as spectral lines in the transform. Exercises permit further exploration of the Nyquist frequency and illustrate the relationship of resolution to number of samples. At the end, the students perform an integral transform of the same waveform. The second document, FT2IR.mcd, demonstrates how spectral information is coded in an interferogram and how the interferometric data limits resolution in the spectrum. In FT2IR.mcd, the inverse FT is used to generate an interferogram from a spectrum with two notches representing absorption. The third document, FT3Pulse.mcd, demonstrates that a short sample of a wave must contain a range of frequencies. In the fourth document, FT4FreeIndDecay.mcd, free induction decay (FID) and its Fourier transform are explored and related to NMR signal analysis. The entire set of documents contains many student exercises and handson activities for learning the concepts presented.  
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Comments to: Mark Iannone at miannone@marauder.millersv.edu  
©Copyright 1998 by the Division of Chemical Education, Inc., American Chemical Society. All rights reserved. For classroom use by teachers, one copy per student in the class may be made free of charge. Write to JCE Online, jceonline@chem.wisc.edu, for permission to place a document, free of charge, on a class Intranet.  