From the Online E2E Forum

July 17, 2006

3 Min Read
From the Online E2E Forum

Q: Rockwell Automation's Motion Analyzer 4.2 and alpha gear's Cymex 3.0 provide easy-to-use design tools for motion control. We investigated both but would like your feedback.

— Editorgirl35

A: Definitely Motion Analyzer. Not only is MA stable but it also has a lot of features. One more good thing is that I have heard they are coming up with 4.3 soon. Let's wait. Do you know that MA now has extensive analysis like tolerance analysis, design analysis and a lot more? It also supports products like Brake Modules and has an advanced motor model.

— Ricardo

Q: Just about any consumer electronics product can be used in a stationary or moving vehicle. This includes cell phones, PDAs, computers, and audio and DVD players. The cell phone already is a target of legislation in many states for its potential to distract the driver. Is the driver's common sense over the entire population of drivers enough to prevent an increasingly dangerous situation as these other products' usage in the vehicle proliferates?

— AZ Auto Guy

A: That's something I've been wondering about too. If it's illegal to use your cell phone while driving (which I think it should be as I've been almost creamed by nut jobs yakking on their phones!) what about having a DVD player up front? That seems like it would be pretty distracting as well. And I certainly wouldn't want to see someone surfing the net while driving! (Although I would love to do that on a long road trip, but only as a passenger.)

— solincsteve

Q: Do data-acquisition systems always require an anti-alias filter between the signal and the analog-to-digital converter?

— PaulM

A: An anti-alias filter is not a requirement. If you have a signal that lacks harmonics or noise above the voltage represented by the voltage "weight" of your ADC's least-significant bit (LSB), you may get away without a filter.

When I designed data-acquisition systems that interfaced to chemical-analysis instruments, for example, I knew the signals had no components that would amount to more than about half the ADC's LSB. In this case, the signals went into instrumentation amplifiers and then on to the ADC. Analyze unknown signals in the frequency domain so you know the frequencies and corresponding signal "power" your data-acquisition system must deal with. You may find you have harmonics or noise you never knew existed. An anti-alias filter may provide a less-costly route than trying to figure out the source of signals aliased into the data you acquire.

Over-sampling ADCs can often get away without a filter, but that's a topic for another thread or reply. Anyone want to chime in on oversampling converters?

— Jtitus

For more Q&A's and to join the conversation online at the Design NewsE2E forums, go to http://rbi.ims.ca/4928-549.

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