Specifying & Creating Data-Acquisition Systems, Part 4
6/6/2012
Without more information, you cannot determine whether the samples (black dots) represent data for a 5kHz (blue) or a 52kHz (red) signal, sampled at 47 ksamples/sec.
Thanks, Jon. I agree that it is always better for the data to be "real" and noise eliminated at the source is always best which also eliminates the need for data to be massaged by software - I was just wondering if it was an option in this case. Thanks for the information!
A software algorithm would have the same problem as people. It could not distinguish the points from the "wanted" signal from those points acquired by an almost unlimited number of higher-frequency signals. An anti-alias filter will help. I find it better to eliminate any source of unwanted signals--noise--as close to the source as possible. More about filters and how to choose them in my next column.
Great information, Jon - I love your series and how it addresses so many relevant issues in test engineering. I was wondering since this is a mathematical function - is it possible to write a software algorithm to eliminate the unwanted data points and if so - would a hardware solution (anti-aliasing filter) or a software solution (algorithm) be more advantageous - or is that simply a matter of available resources?
Let me know if you still want more about anti-alias filters. My upcoming columns on oversampling explain how using this technique helps eliminate an anti-alias filter for some measurements.
The Machinist Calc Pro computes speeds and feed rates for milling, turning, and drilling: cutting speed, spindle speed, feed rate (inches/minute), cutting feed, etc.
During a recent meeting with engineering-school faculty and alumni, Contributing Technical Editor Jon Titus talked about whether colleges should educate generalists or specialists. What do you think?
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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
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