Interesting example of Aliasing

Aliasing occurs when your measurement frequency is not fast enough to accurately capture the measured event. In general, you want your measurement device to be one order of magnitude faster than the event being measured.

From Wikipedia: accessed January 9th 2011
"In signal processing and related disciplines, aliasing refers to an effect that causes different signals to become indistinguishable (or aliases of one another) when sampled. It also refers to the distortion or artifact that results when the signal reconstructed from samples is different from the original continuous signal."

Category:

Science & Technology

Tags:

• Pennywhistle
• Productions
• Aliasing

[Supermassively]

Have you been to Sci-Quest in Huntsville?

[destinws2]

@Supermassively

IMA member

[danielc0307]

very cool! Ever been to the Museum of Science and Industry in Chicago?

[destinws2]

@danielc0307

No, sounds like a place I would love. This one is inBirmingham... It's pretty good.

[blueAgentAj]

You're at the McWane Center! Such a cool place.

[onevim]

Cool apparatus, but very shaky camera work.

[MarcPopeTV]

if you've got a sample rate of 20Khz (to keep it simple) and a sine 15kHz, the 5kHz that is over the threshold bounces off the Nyquist frequency and is mirrored giving you a signal of 5kHz instead.

so you see, aliasing "is" the false reading, not what causes it. i'm not sure about other disciplines but in the audio engineering world, having a look at the Nyquist theorem and then aliasing will help you to understand.

[MarcPopeTV]

That explains what causes aliasing (in a very crude way) - this is not what aliasing is.

[kmaj007]

Excellent, just read the strobe demonstration on a disc, your video cleared my concept...ta mate...!!

[aznDrgoonZ3]

I'm learning about waves in physics right now :D and my teacher has one of these in the classroom that he made. Thanks for explaining a bit more!

[rgomess]

learn to shoot first

[Supermassively]

@destinws2 Nice! I'd love to live in Rocket City. Such an awesome area.