Document Type
Conference Proceeding
Abstract
The phenomenon of aliasing is important when sampling analog signals. In cases where the signal is bandlimited, one can avoid aliasing by ensuring that the sampling rate is higher than the Nyquist rate . But in cases where the signal is not bandlimited , aliasing is unavoidable if the signal is not filtered before it is sampled. It is then crucial to understand the phenomenon in order to estimate the distortion generated when the signal is reconstructed from its samples. Using the software package MATLAB by MathWorks, Inc ., two examples are presented. The first is a pure sinusoid which is sampled at both higher and lower than the Nyquist rate , and the frequency spectrum of both sampled sinusoids are compared to illustrate the effect of aliasing. The second and more interesting case is a square wave which has an unlimited bandwidth. The square wave is a periodic wave that has Fourier expansion with odd harmonics only, the amplitudes of which drop as lin. A square wave is synthesized using MATLAB and its Fourier transform is presented graphically (The synthesized square wave inherently produces aliased components) . The odd harmonics and the aliased components seen on the graph are analyzed and compared to the predicted theoretical results. Graphs generated by MATLAB accompany the analysis for both signals.
Repository Citation
Neeman,, Sol Ph.D., "Using MATLAB to Illustrate the 'Phenomenon of Aliasing'" (1995). Engineering Studies Faculty Publications and Creative Works. 8.
https://scholarsarchive.jwu.edu/engineering_fac/8
Included in
Computer Engineering Commons, Electrical and Computer Engineering Commons, Engineering Science and Materials Commons, Mechanical Engineering Commons, Operations Research, Systems Engineering and Industrial Engineering Commons, Other Engineering Commons
Comments
Conference proceedings from the 1995 American Society of Engineering Educators (ASEE) Annual Conference.