Hi, Rob. You can get some unusual results because signals at higher frequencies alias, or fold, into the bandwidth over which you want to make measurements. The alising arises from the sampling of signals at discrete time intervals. Upcoming columns get into more details and explain how to use aliasing to "shift" signals to lower "frequencies" on purpose. Stay tuned. --Jon
Hi Jon, As always, great technical article. I'll definitely be waiting for the additional articles on Anti-Alias Filters so I can share this information with my Integrated Circuits class at ITT Tech Institute. Keep the tech articles coming!
IF there are signals with frequency content above the Nyquist frequency ( half the sample rate ), AND analog anti-aliasing filtering is not used prior to Analog to Digital Conversion, the signals will appear as signals between DC and the Nyquist frequency ... AND once digitized, the aliased signals cannot be separated nor recognized as being invalid - can be a Major issue.
From my experience anti-alias filtering is usually a compromise and typically you set the sample rate higher than the desired max needed frequency to allow some roll-off without significantly compromising the data of interest.
Modern ADC systems typically sample at their max rate and use anti-alias filters set appropriately high... the data is then Digitally low pass filtered and Decimated to create lower effective sample rates with no analog anti-aliasing filter artifacts...
Lantronix Inc. has expanded its line of controllers for sensor networks with the release of a rugged controller that improves management of automation systems used in a number of industries, including manufacturing, oil and gas, and chemicals.
Inspired by the hooks a parasitic worm uses to penetrate its host's intestines, the Karp Lab has invented a flexible adhesive patch covered with microneedles that adheres well to wet, soft tissues, but doesn't cause damage when removed.
A quick look into the merger of two powerhouse 3D printing OEMs and the new leader in rapid prototyping solutions, Stratasys. The industrial revolution is now led by 3D printing and engineers are given the opportunity to fully maximize their design capabilities, reduce their time-to-market and functionally test prototypes cheaper, faster and easier. Bruce Bradshaw, Director of Marketing in North America, will explore the large product offering and variety of materials that will help CAD designers articulate their product design with actual, physical prototypes. This broadcast will dive deep into technical information including application specific stories from real world customers and their experiences with 3D printing. 3D Printing is