e- / DN Uncertainty

[MY PIXEL]

Posted to CCD-world:
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***********jj
Harry,

These are theoretical discussions where CTE is perfect and there is no read
noise. You are right in the practical sense. For now we still believe the
uncentainty is (need to find those past calculations):

Uncertainty in e-/DN  =  (2)^1/2  x  K (e-DN)  /  (Np)^1/2 

where Np are the number of pixels sampled.

PS. Harry are you going to SPIE in Hawaii in March? The equation is derived
somewhere in class notes.

************jj

In a message dated 98-01-25 15:43:10 EST, or_marshs at integrityonline.com
writes:


 Jim--
 I think what Paola is trying to state is that when the signal is reduced,
 there is more error in the encoding of the signal [if one gets down in the
 <1000DN range), and other errors (like the CTE floor creeping up to the
 noise floor).
 
 I found that e-/DN calculations were fairly accurate down to about 1/8th
 scale on the ADC, or about 1000 e- CCD-wise.
 
 	HHM >>
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