National Instruments NI 9229 - Manual (Page 11)

© National Instruments Corp. 11 NI 9229/9239
The NI 9229/9239 analog input channels are floating with respect
to earth ground and each other. The incoming analog signal on each
channel is conditioned, buffered, and then sampled by a 24-bit
Delta-Sigma ADC.
Each channel provides an independent signal path and ADC,
enabling you to sample all four channels simultaneously. Refer to
Figure 5 for an illustration of the circuitry for one channel.
Figure 5. Input Circuitry for One Channel of the NI 9229/9239
NI 9229/9239
AI+
AI–
ADC
Amplifier
Overvoltage
Protection
Prefilter