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NI PXIe-4464 Calibration Procedure
AI Noise Verification
Note
This performance characteristic is not affected by adjustment. Consequently,
reverification after adjustment is not necessary.
Complete the following steps to verify the AI noise:
1.
Using the equipment described in Table 1, connect a BNC shorting cap to each device input
channel.
2.
Create and configure an AI voltage task on the device as shown in Table 10.
3.
Start the task.
4.
Acquire readings with the NI PXIe-4464.
5.
On a per channel basis, compute the standard deviation of the acquired samples.
6.
Stop and clear the task.
7.
Compare the computed values to the appropriate limits in Table 11. The standard deviation
is the input noise at the -20 dB gain setting at the 204.8 kS/s sample rate.
Table 10.
AI Noise Verification Configuration
Configuration
Value
Physical channels
Dev_name
/ai0:3
Gain
*
-20 (dB)
Coupling
DC
Terminal configuration
Pseudodifferential
Excitation (IEPE)
0 (A)
Acquisition mode
Finite number of samples
Rate
204800.0
Samples per channel
102400
*
Refer to Table 3 for the maximum and minimum voltages to specify to ensure the specified gain range
is used on the module.
Table 11.
AI Noise Limits
Device Gain (dB)
f
s
= 51.2 kS/s
Max (µV
rms
)
f
s
= 204.8 kS/s
Max (µV
rms
)
-20
197
445
-10
117
243
0
14.0
32.9
