Hi Austin
> Hi Toooooodd,
>
>>> Ouch. Sigh. Dynamic range:
>>> 1. The difference, in decibels, between the overload level and
>>> the minimum
>>> acceptable signal level in a system or transducer.
>>> <snip>
>>> 5. The difference between the maximum acceptable signal level and the
>>> minimum acceptable signal level.
>>> (Modern Dictionary of Electronics, 6th ed.)
>>>
>>> Austin is, of course, right on this one.
>>
>> I don't claim to know DyR better than anyone else but I have followed the
>> discussion for some time. So, I'm not sure why what you cite
>> above supports
>> Austin any better than Julian.
>>
>> My reading of Julian is that he is in full agreement/compliance
>> with what is
>> written above.
>
> Possibly, but it depends on how it and the terms used are "interpreted". I
> don't recall who believes what means what, but the terms CAN be
> ambiguous...and the ones cited certainly are.
Of course I'm just a novice, so I don't mean to sound confrontational or
argumentative. I respect your take on this, so please know my tone is an
asking one...
But isn't it pretty obvious that the above is simple speaking to a range
between noise and distortion -- IOW, the useable range of the device? Yes,
the specifics are somewhat ambiguous, but is the concept really so
ambiguous. If it were as you do it wouldn't the definitions spell that out
better? While I know better than to think I know better than you, it does
seem you are trying to fit YOUR terms (I've never seen you cite a source
that uses them. Though you say the ISO agrees with you, or you agree with
them, they certainly don't use your terms (do you have that PDF btw, if so
would you email it to me privately???)
>> I believe he feels DyR is exactly: 5. The
>> difference between
>> the maximum acceptable signal level and the
>> minimum acceptable signal level.
>> (Modern Dictionary of Electronics, 6th ed.)
>
> Again, what does "minimum acceptable signal level" mean? Is that the
> minimum measurable change in signal, or the lowest "voltage" the signal can
> attain.... What does "maximum acceptable signal level" mean? The largest
> amplitude the signal can attain, or the highest voltage the signal can
> attain?
>
>> My reading of Austin is that he believes DyR is the The difference between
>> the maximum acceptable signal level and the
>> minimum acceptable signal level, divided by noise, (where noise is
>> typically/frequently specified as 10.
>
> It depends. Using the definitions above, and using what I believe the terms
> mean, I'll define the terms here...
>
> Per definition 5 (because it's easier and more to the point):
>
> "maximum acceptable signal level" means the largest amplitude. It is
> EXACTLY the same as the largest voltage the signal can attain, minus the
> minimum voltage the signal can attain.
As limited by what? On the low end it's often noise, no?
> "minimum acceptable signal level" means the smallest amplitude that can be
> measured. Typically, this is noise.
If the answer above is yes, would that not lead to a double accounting of
noise? I anticipate that your answer will be "sometimes it's limited by
noise but not always". If so, could you speak to the case when it is?
> If that is the definition of those two terms, than #5 is correct. You can
> extrapolate those definitions to #1 if you like, and therefore it's correct
> too...
>
> What happens is people don't understand the CONCEPT of dynamic range, and
> therefore don't understand what the terms actually mean...and draw a
> different understanding as to what dynamic range is.
However, the definitions quoted over and over never mention DyR being a
range divided by noise, just a range (max to min). You've always maintained
DyR is a tonality, or resolution, but provide no authoritative definitions
to back that up. (This doesn't mean I'm saying I think you are wrong. I know
I don't know enough to judge. ;-)
You've always referred to the Higgins diagram to illustrate YOUR terms, and
it is a convenient diagram for doing so, but I've seen the diagram in it's
ENTIRETY (I saw that you were only presenting a portion of it out of
context. The point of the diagram appears to be simply to illustrate the
obvious, that one needs to map the DyR of an input to the lower DyR of the
medium that will hold it to prevent clipping) along with the text that
supports it, and Higgins in no way DEFINES the terms as you do. Though he
does not refute them either I should add!
>>> Comment: this went back and forth interminably, and I think most of that
>>> could have been avoided by actually quoting standard
>> definitions of the term
>>> and working from there.
>>
>> Just curious, would those standard definitions and terms BE what you quote
>> above? If so, lets see if it makes a difference. I doubt it will...
>
> That's the point, there ARE no standard definitions and terms...
That's been my point throughout most of these discussions. The CONCEPT of
DyR would appear, at least to me, to be simply: the ratio or difference
(depending on whether the values are in log form) of the max to min of
something. How max and min are defined may vary from lab to lab and from one
field to another.
Since there are no standard definitions why is this topic spoken of as
though one person is right or wrong, when there clearly is NO
"standard"?
Todd
PS, In my research of this topic I found these sources. When I found them I
realized I'd never really get a grip on the matter. I think it illustrates
what I mean by different labs taking their own approach. Trade you these two
for the ISO PDF ;-)
----------------------------------------------------------------------------------------
Unsubscribe by mail to listserver@halftone.co.uk, with 'unsubscribe
filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or
body
