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**To**:**Loopers-Delight@loopers-delight.com****From**:**Bill Fox <billyfox@soundscapes.us>****Subject**:**Re: sample rate****Date**:**Sun, 25 Dec 2005 13:29:04 -0500**

Adrian Bartholomew wrote: > this is where SOME info is worse than NO info. > dude think about it. > u have a wave at 1/2 the sample frequency. think about it like > connect-the-dots. > the only ones u can plot are the max(positive) and min(negative) > points of the wave. NOW connect the dots and what do u have. thats > right a sawtooth wave. even if the original was a sine. > but at least u have the frequency. forget about phase what about shape > or tone? > even if u sampled at a frequency high enough to give u three or even 4 > points to connect, its STILL approximate, very far from the shape of > the original and certainly not "all the information of the original > signal". Dude, there is no connect the dots in a sampled system. Electronically, the dots AREN'T connected. The DAC outputs a stepped series of voltages that feed a reconstruction filter, i.e. an LPF. This filter takes your so-called sawtooth, filters out everything above the LPF's pernamently set cutoff frequency and voila, you get a sine wave! Think about it a minute. The LPF is set to filter out everything above (0.5)fs, where fs is the sampling frequency. fs is the first possible overtone of ANY waveform that isn't a sine. What you think is a sawtooth is actually a square wave. But you won't hear anything except the original sine wave being reconstructed. The lack of information or understanding is yours. I can't give you the engineering background required to prove that I'm right. You'll have to spend a few years first, learning higher mathematics andinformation theory. But every CD player, every DVD player, every minidisc, DAT, and iPod prove me right. Cheers, Bill

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*From:*Bill Fox <billyfox@soundscapes.us>

- Re: sample rate
*From:*Adrian Bartholomew <adrian@bartholomusic.com>

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