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Re: sample rate
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
> 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
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
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.