Some People Haven't a Clue
"Scott" wrote in message
...
On Sunday, February 17, 2013 10:26:26 AM UTC-8, KH wrote:
On 2/17/2013 7:42 AM, Scott wrote:
On Saturday, February 16, 2013 12:11:46 PM UTC-8, Audio_Empire wrote:
Modern ADCs and DAC chips are
laser trimmed so that quantization error is kept low to non-existent,
IIRC.
It may be low but it is not non existent.
Uhm, as Dick Pierce just pointed out, by providing a clear example of
the mathematical mechanism involved (thx Dick, a simple and illustrative
treatise), it *is* non-existent. How about you provide some evidence to
the contrary?
No that is not what he pointed out. He made a big deal about the
terminology and pointed out how dither works to *lower* the
distortion. Some distortion is still there. If you think it isn't you
are simply wrong.
I think we're on the brink of an exceptional claim. Properly applied TPDF
dither can be mathematically proven to competely decorrelate the first
moment of the quantization error (AKA distortion amplitude) and make it
statistically independent of the signal. In layman's terms that means
"nonlinear distortion amplitude sums to zero". Furthemore, properly applied
TPDF dither can be mathematically proven to competely decorrelate the second
moment of the quantization error (AKA distortion power) and make it
statistically independent of the signal. In layman's terms that means
"nonlinear distortion power sums to zero".
I can see the correlation summing to zero and still be non-zero at times,
but for the square of the correlation to sum to zero, AFAIK the correlation
has to be solidly zero at all times.
The only case where the sum of the square of an error signal sums to a
non-zero number that comes to mind is when the error signal is imaginary.
;-)
As a practical matter it can be observed that there are many different kinds
of dither including TPDF dither that randomize the quantization error to the
point where electrical and mathematical means of detecting it are completely
frustrated.
This information has been known and widely disseminated without controversy
for several decades.
I would be very interested in knowing what more recent authority could be
formally cited that would change that situation.
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