Multichannel Scanning Considerations; Figure 3-5. Dither - National Instruments DAQ PCI E Series User Manual

Chapter 3 Hardware Overview
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 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
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0 0 100 100
c. Dither enabled; no averaging c. Dither enabled; no averaging

Multichannel Scanning Considerations

PCI E Series User Manual
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You cannot disable dither on the PCI-MIO-16XE-10,
PCI-MIO-16XE-50, PCI-6031E, PCI-6032E, or PCI-6033E. This is
because the ADC resolution is so fine that the ADC and the PGIA
inherently produce almost 0.5 LSBrms of noise. This is equivalent to
having a dither circuit that is always enabled.
Most of the PCI E Series boards can scan multichannels at the same
maximum rate as their single-channel rate; however, pay careful
attention to the settling times for each of the boards. The settling time
for most of the PCI E Series boards is independent of the selected gain,
even at the maximum sampling rate. The settling time for the very
high-speed boards is gain dependent, which can affect the useful
sampling rate for a given gain. No extra settling time is necessary
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 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 d. Dither enabled; average of 50 acquisitions

Figure 3-5. Dither

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