Quote:
Originally Posted by Stonius
Is it? I must be reading it wrong, because it looks to me like here are no 'Signal' terms, they are all Nsig which I assume means 'signal noise'. To make a ratio there must be some mention of the signal, surely?
What is NPix? Pixel noise is new to me. Does it have another name?
Cheers
Markus
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Well I can't say for sure what may have been intended, but there is certainly another noise term (error) that often goes unmentioned: the quantisation error. It is the error one sees in a digital system associated with assigning
a continuous analogue value in to
a discrete range of analogue values ( a pigeon-hole) in readiness and suitable for Analogue to Digital Conversion at a given bit depth. It's sort of a round off error which worsens with lower digital word bit depth.
As an example an analogue transducer may return an actual reading of say 1.7320612 Volts, but in being digitised
given a possibly limited digital word depth, may only be able to placed in to a discrete range of values (pigeon-hole) of say 1.70 to 1.74 Volts (mid-point 1.72 Volts). The difference between the continuous analogue value (1.7320612 Volts) and the pigeon hole mid-point (1.72 Volts) is 0.0120612 Volts and can be thought of as a sort of rounding-off error associated with pigeon holing the data. It's called the quantisation error in a digital system, but I suppose one could look upon it as a sort of noise, in that like the shot noise for example, it takes us away from the true value of the signal intensity for a given measurement.
Best
JA