17-2000 C
2020-09-17
47(50)
ADQ8-8C Manual
17-2000 C 2020-09-17
47(50)
7.10 Over-range and under-range
The over/under-range bit in the header indicates that over-range or under-range occurred at one or
several samples within the record and at any stage in the signal chain. The result of the over-range is
not straightforward to predict, see
.
Example 6:
shows under-range in ADC before the Offset calibration. The result is that the
digital code where the under-range occurred is not the maximum code.
#
DESCRIPTION
a
ADC with offset.
b
Digital offset calibration.
c
Digital baseline stabilizer that dynamically adjust baseline to zero. That is adjust the offset. Under-range has
already occurred prior to this stage.
d
Acquisition create a header which contain over/under-range indication.
e
The analog input signal with offset. The ADC also contribute to the offset.
f
Digital calibration cannot account for offset on the analog signal. Under-range occur when signal is out of
range on the negative side.
g
The DBS fine-tunes the offset, that is add a value to the signal. Then the under-range is not at the minimum
digital code anymore.
h
Overflow indication is set when over/under-range occur and is kept for the record.
Figure 36: Under-range in the ADC calibration.
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