synopsis: derivation of the statistical uncertainty
of the signal per integration ramp.
limitations and applicability:
For ramps with 3 non-destructive read-outs no uncertainty in the signal
can be derived. The signal uncertainty
is then set to zero.
description:
The signal (in V/s) per ramp is derived by fitting a first order polynomial
to the ramp. The uncertainty is obtained from the mean of the residuals
computed from the difference between the read-out and model voltages, these
uncertainties are used as weights in the determination of the mean signal
per chopper plateau or raster point.
purpose correction:
Determination of a signal from the slope of an integration ramp.
uncertainty/noise introduced:
The scatter of the individual read-outs around the fitted slope of the
ramp is a measure of the photon and detector noise. The scatter is also
influenced by the previous correction steps.
For ramps with 3 non-destructive read-outs only 2 read-outs are used for
ramp fitting. The uncertainty in the signal is set to zero and the mean
per chopper plateau or raster point is not weighted.
auxillary data:
None
keyword(s):
| RAMPPCT: | percentage of ramps used for signal average | SPD header |
| RAMPUSET: | percentage of time used for signal average | SPD header |