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In Reply to: Did we just go around in a cricle? posted by Commuteman on August 22, 2003 at 15:58:07:
HowdyMy whole point is that the sample rate isn't in and of it's self responsible for quantizing phase. As I point out in my response to John, with no quantization of level, all phases are possible. When you quantize the level things are more interesting and the sample does come into the picture, but it's been many years since I took DSP courses and my books are packed so I won't even try to come up with the relationship of quantization of level to resultant phase effects.
Perhaps Werner or some one else who does this stuff actively for a living will chime in.
Follow Ups:
you're right that anything up to half the sample frequency will be perfectly reconstructed (assuming no jitter, of course....)Now how does that jive with the fact that we can apparently hear arrival time differences down to around 20uS, or half a sample period? Doesn't sound like a CD has that level of time resolution.
I know I'm mixing up a bunch of concepts here, which is why I'm having trouble connecting the dots....
Peter
HowdySince you can represent any given sine with an arbitrary phase, you just add enough up to give you the attack or transient you want with what ever phase you want. (Limited by Nyquist for highest freq and ultimately the level quantization introducing enough errors which smear the time resolution.)
CDs can represent left and right channel phase differences which are quite small, smaller than a sample period. This is probably how great CD players with low jitter get a precise soundstage, even for higher freq instruments like the triangle, etc. (I'm just hand waving here.)
I don't know the exact time resolution of Redbook, but the simplistic argument that it's one sample period is clearly hooey.
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