National Instruments E Series - Manual (Page 29)

Chapter 3 Hardware Overview
 National Instruments Corporation 3-7 DAQCard E Series User Manual
You cannot disable dither on the DAQCard-AI-16XE-50. This is
because the ADC resolution is so fine that the ADC and the PGIA
inherently produce more than 0.5 LSB rms of noise. This is equivalent
to having a dither circuit that is always enabled.
Multichannel Scanning Considerations
All of the DAQCard E Series cards can scan multiple channels at the
same maximum rate as their single-channel rate; however, pay careful
attention to the settling times for each of the DAQCards. The settling
time for most of the DAQCards is independent of the selected gain,
even at the maximum sampling rate. The settling time for the high
channel count and very high-speed cards is gain dependent, which can
affect the useful sampling rate for a given gain. No extra settling time
is necessary between channels as long as the gain is constant and source
Figure 3-3. Dither
100 200 300 400 0 500
-4.0
-2.0
0.0
2.0
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LSBs
LSBs LSBs
LSBs
6.0
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6.0
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a. Dither disabled; no averaging b. Dither disabled; average of 50 acquisitions
c. Dither enabled; no averaging
100 200 300 400 0 500
-4.0
-2.0
0.0
2.0
4.0
-6.0
d. Dither enabled; average of 50 acquisitions
LSBs
LSBs LSBs
LSBs
6.0
100 200 300 400 0 500
-4.0
-2.0
0.0
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4.0
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6.0
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6.0
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6.0