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Politics : Foreign Affairs Discussion Group -- Ignore unavailable to you. Want to Upgrade?

To: Sun Tzu who wrote (171915)	10/4/2005 7:15:34 PM
From: neolib	Read Replies (1) \| Respond to of 281500

I refer you now to the sampling theorem in DSP; samples measuring at more than half the gradations of your measuring stick will all register as being at the highest level...it seems to hold true in politics as well. Not actually true. Signal content which has a frequency > 1/2 the sampling frequency gets aliased to lower frequencies, that is they show up as bogus low frequency content. Where they show up depends on their actual frequency to the sampling frequency. An example that many people have experienced is watching a fast spinning object under 60hz florescent light, if the spinning object has spokes, or some radial pattern like a movie reel, it will appear to be rotating much slower. The speed at which it appears to be rotating can be made to vary dramatically if the spinning object is running around 3600 rpm or some integer divisor or multiple of same (or some product based on the pattern geometry as well). The difference in frequency between the spinning geometry and sampling light (60Hz in this case) is called the beat frequency. Another example of beat frequency that you may have physically experienced is the low frequency throbbing heard inside the cabin of multi-engine aircraft, especially prop driven ones, when the engine rpm is slightly out of sync. The beat frequency is often a few Hz or sub one Hz in this case.