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Subsections



14.4 Selection of Readouts


Description Parameter:	 Section 4.3.1
Processing Level:	 SPD
Usage in processing:	 Section 7.2.2
File Type:		 Binary Fits Table
Number of Records:	 8
File Names:		 PSELNDR 

It has been observed that the first few readouts of each integration ramp do not increase in a linear way but can stay flat for a while or can even decrease. The disturbance is due to the preceding reset and is a switch-on effect of the integrator which is independent of the reset voltage level. This effect is not related to the voltage dependent non-linearity for which the corrections are stored in the Cal-G linearisation files (Section 14.5). The best correction method so far is to discard these readouts. The number of readouts that should be removed is a function of the number of readouts per ramp. The optimum values have been determined in flight.

In total there are 8 records, each record gives the number of readouts to be discarded for a given NDR value. The record ordering is given in Table 14.3.


Table 14.3: Relation between record number and NDR in PSELNDR.
Record number of non- Record number of non-
number destructive readouts number destructive readouts
1 0 5 15
2 1 6 31
3 3 7 63
4 7 8 127


14.4.1 Product PSELNDR: PHT non-destructive readout selection

Binary FITS table with record length 32. The record fields are:


Field	 Offset	Number	Type	Description
PP1SNDR	 0	1	I*4	NDRs to discard for PHT-P1
PP2SNDR	 4	1	I*4	NDRs to discard for PHT-P2
PP3SNDR	 8	1	I*4	NDRs to discard for PHT-P3
PFILSNDR 12	1	I*4	Filler
PSSSNDR	 16	1	I*4	NDRs to discard for PHT-SS
PSLSNDR	 20	1	I*4	NDRs to discard for PHT-SL
PC1SNDR	 24	1	I*4	NDRs to discard for PHT-C100
PC2SNDR	 28	1	I*4	NDRs to discard for PHT-C200


next up previous contents index
Next: 14.5 CRE Linearisation Corrections Up: 14. Calibration-G Products Previous: 14.3 DIE Power Calibration
ISO Handbook Volume IV (PHT), Version 2.0.1, SAI/1999-069/Dc