"Todd Flashner" <tflash@earthlink.net> writes:
>>>>>>>>>>>
Yes, I suppose if one is convinced that DYR is a resolution that is the way
they'd have to approach it as such, but David, tell me, have you seen a
cited reference that supports that approach?
<<<<<<<<<<<<
"The dynamic range of a digital signal is the ratio of the maximum
full-scale signal representation to the smallest signal the DSP or data
converter can represent. For an N-bit system, the ratio is theoretically
equal to 6.02N. "
>>>>>>>>>>>>>
I've wanted to believe Austin is right for a long time, but there is just
massive evidence against it. Do you really see the ISO's: (Dmax - Dmin)
supporting that, or Analog Devices: (Peak Level) - (Noise Floor) supporting
that?
<<<<<<<<<<<<<
You left out the subscripts: (Peak Level)dB - (Noise Floor)dB. As has been
said before, those are log values. Subtraction of log values _is_ division.
Thus the dynamic range, by those definitions, is exactly the same as it is
everywhere else: the ratio of the max signal to the noise.
>>>>>>>>>
Isn't it more "obvious" to presume that "Dmin" is a single value, as is
"Peak Level", and if they WERE a range extra attention would be paid to that
issue by the definitions? Would they really leave it vague for most EEs to
be mistaken?
<<<<<<<<<<
It's not vague, it's correct....
>>>>>>>>>>
What Julian said about the term Dynamic Range makes sense: if
it's not really a range, wouldn't the definitions go out of their way to
have it be known it is a resolution, a resolution which is called a range,
and as such all max signal levels need to be understood as being relative to
min signal levels before they can be applied in the equation? Shouldn't they
hint somehow that while the equation they lay out may look like x/z, or x-z,
what it will look like in use will be (x-y)/z or (x-y)-z? In time wouldn't
the confusion of students of the subject demand they pay attention to this
possible source of massive confusion (and upset ;-)) ???
<<<<<<<<<<<<<<<<
Dynamic range is _equivalent_ to a bit depth because a digital
representation at a given bit depth has a quantization error, or
quantization noise, of +/- 1/2 lsb. Thus a bit depth involves an implicit
noise level of exactly one unit over the range of values it can represent.
Thus dynamic range (a logarithm of a ratio) and bit depth (which is the base
2 logarithm of it's largest value) are _equivalent_.
>>>>>>>>>>
PS, I like the way your mail program quotes me, what do you use?
<<<<<<<<<<
I insert the "<<<<<<<<" by hand, since depending on the headers, dear old
brain dead Outlook Express fails to insert the normal > quote marks.
Grrrrrrrrrrrr.
David J. Littleboy
davidjl@gol.com
Tokyo, Japan
----------------------------------------------------------------------------------------
Unsubscribe by mail to listserver@halftone.co.uk, with 'unsubscribe
filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or
body
