RE: Quick note on Disk 18a

["Albertson, Chris" <CAlbertson@primeadvantage.com>]

I'm suggesting fixes really as a way to understand what's going on.
OK I believe that the sky background in a given frame has more
noise than the ADC chip introduces.  Now lets say we took an
average of 100 frames.  What would you expect the major noise source
to be?  The sky is down by a factor of 10 = sqrt(100) but I think
non-random systematic errors get worse as you add them.

> -----Original Message-----
> From: Tom Droege [mailto:tdroege@veriomail.com]
> Sent: Monday, May 21, 2001 9:44 PM
> To: Albertson, Chris; tass@listserv.wwa.com
> Subject: RE: Quick note on Disk 18a
> 
> 
> Hey!  You guys are worrying about nits when it is raining boulders.
> 
> Yes it is true that most successive approximation ADCs have a 
> momentary 
> fairly well defined differential linearity error.  But is is going to 
> change with the temperature and time of day and small 
> variations in the 
> power supply voltages.  It is not worth trying to calibrate.  
> I attempted 
> to match the ADC quality to the data.  It is way overkill.  
> This ADC is 
> always good to a few ADU.  The differential linearity is a 3 or 4 
> ADU.   The integral linearity is somewhat worse, but it is 
> normally better <SNIP>
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