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3.11 Signal averaging per chopper plateau

synopsis: derivation of the weighted standard deviation of the weighted mean signal per chopper plateau. This standard deviation will be used as the statistical uncertainty of the weighted mean signal.

limitations and applicability:
no limitations, always applied.

description:
Computation of the weighted mean of all valid signals on a chopper plateau or raster point (a staring measurement is regarded as one single chopper plateau).

purpose data reduction step:
Determination weighted mean signal and statistical uncertainty.

uncertainty/noise introduced:
${\Delta}s$ (sect. 3.5) is used as weight. Ramps with only 2 valid read-outs are weighted out since their weight have been set to zero. If all ramps in a measurement have 3 non-destructive read-outs per ramp (see section 3.5) all signals get the same weight by setting all weights to 1. This processing step yields the statistical uncertainty in the signal distribution.

auxillary data:
Number of valid signals on the plateau for averaging.


next up previous contents
Next: 3.12 Chopper vignetting/offset correction Up: 3. Derive SPD level Previous: 3.10 Transient recognition
ISOPHOT Error Budgets: Derive_SPD Processing Steps, Version 1.0, SAI/98-091/Dc