On 2/14/2013 8:06 AM, Scott wrote:
On Wednesday, February 13, 2013 8:05:12 PM UTC-8, KH wrote:
On 2/13/2013 3:10 PM, Scott wrote:
On Wednesday, February 13, 2013 11:54:15 AM UTC-8, Dick Pierce wrote:
Scott wrote:
Maybe in some other neck of the woods. But all too often I
see some folks dragging out Shannon/Nyquist and saying "see digital
IS perfect."
I would like to see a direct quote from someone who
made this assertion.
If you are asking for one I'll just show you one from one of my
favorite sources of misinformation.
"The Nyquist theorem (which is mathematically proven) says that
the exact waveform can be reproduced if the original signal is
frequency limited to less than half the sampling frequency."
http://www.hydrogenaudio.org/forums/...yquist+perfect
IMO "exact" and "perfect" are synonymous as used here. I can find
more but you only asked for one.
You seem to have left out the clear caveat in the very next sentence;
"The word "exact" gets a little shaky if the initial assumptions aren't
met (example: each sample is taken exactly on time.)"
Seriously? You think that makes it correct? You think that is all it takes?
Well, yes. In fact that is all that is required to make it "correct".
It still says *nothing* about "digital is perfect".
from which it is
abundantly clear that the OP was decidedly Not implying "digital is
perfect", merely that if "done perfectly" - an impossibility - the
resulting waveform would be perfect, which IS clearly supported by
information theory.
Really? So you don't believe in quantization error?
In "sampling"? No. And sampling is what that statement relates to. I
believe Dick Pierce has sufficiently addressed that.
And of course, you excised the context of the statement as well, in that
it was a response to the ludicrous claim that "...converting an analog
signal into a discrete-time one (as it happens when converting from
analog to digital) destroys the phase information in the two top octaves
of the resulting spectrum. In a CD-standard digital recording, all phase
information are lost from 5.5kHz up to 22kHz,"
I don't see how the quote you provided has ANY relevance to your claim.
People often see what they want to see.
Yes, they do. And no one, with even a superficial objective reading,
would construe the post you cited as saying "digital is perfect".
Keith