Multichannel Scanning Considerations; Figure 3-2. Dither - National Instruments VXI-MIO 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
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

VXI-MIO Series User Manual
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You cannot disable dither on the VXI-MIO-64XE-10. This is because
the ADC resolution is so fine that the ADC and the PGIA inherently
produce almost 0.5 LSB rms of noise. This is equivalent to having a
dither circuit that is always enabled.
All of the VXI-MIO Series modules can scan multiple channels at the
same maximum rate as their single-channel rate; however, you should
pay careful attention to the settling times for each of the modules. Refer
to Appendix A, Specifications, for a complete listing of settling times
for each of the VXI-MIO Series modules.
When scanning among channels at various gains, the settling times may
increase. When the PGIA switches to a higher gain, the signal on the
previous channel may be well outside the new, smaller range. For
instance, suppose a 4 V signal is connected to channel 0 and a 1 mV
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

Figure 3-2. Dither

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