Figure 3-3. Dither; Multichannel Scanning Considerations - National Instruments E Series User Manual

LSBs LSBs
6.0 6.0
4.0 4.0
2.0 2.0
0.0 0.0
-2.0 -2.0
-4.0 -4.0
-6.0 -6.0
0 0 100 100
a. Dither disabled; no averaging
LSBs LSBs
6.0 6.0
4.0 4.0
2.0 2.0
0.0 0.0
-2.0 -2.0
-4.0 -4.0
-6.0 -6.0
0 0 100 100
c. Dither enabled; no averaging

Multichannel Scanning Considerations

National Instruments Corporation
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Figure 3-3. Dither

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.
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
LSBs LSBs
6.0 6.0
4.0 4.0
2.0 2.0
0.0 0.0
-2.0 -2.0
-4.0 -4.0
-6.0 -6.0
0 0 100 100
b. Dither disabled; average of 50 acquisitions
LSBs LSBs
6.0 6.0
4.0 4.0
2.0 2.0
0.0 0.0
-2.0 -2.0
-4.0 -4.0
-6.0 -6.0
0 0 100 100
d. Dither enabled; average of 50 acquisitions
3-7
Chapter 3 Hardware Overview
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DAQCard E Series User Manual