Filtering: Removing Noise from a Distress Signal
Students learn the basic principles of filtering as well as how to apply digital filters to extract part of an audio signal by using an interactive online demo website. They apply this knowledge in order to isolate a voice recording from a heavily noise-contaminated sound wave. After completing the associated lesson, expect students to be able to attempt (and many successfully finish) this activity with minimal help from the instructor.
Imagine you are a NASA engineer and one of your antennas picks up a distress signal, but it is too noisy to understand.Copyright 1991, NASA, Wikimedia Commons http://commons.wikimedia.org/wiki/File:SSF_-_1991.jpg
Electrical engineers who work in image and video processing as well as communications use filters to remove noise from signals before they are delivered to viewers and listeners. Engineers often deal with data collection in which filtering is used to ensure the data is not made useless by unwanted noise.
After this activity, students should be able to:
- Describe a signal by inspecting its spectrum.
- Determine what types of filters are needed to isolate parts of a noisy signal.