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NI 5922 Calibration Procedure
3.
Call
niScope_ConfigureVertical
(niScope Configure Vertical VI) with the
following parameters:
•
channelList
:
"0"
•
Range
: The
Range
value for the current iteration from Table 4
•
Offset
:
0.0
•
Coupling
:
NISCOPE_VAL_DC
•
ProbeAttenuation
:
1.0
•
Enabled
:
NISCOPE_VAL_TRUE
4.
Call
niScope_ConfigureHorizontalTiming
(niScope Configure Horizontal
Timing VI) with the following parameters:
•
minSampleRate
: The
Sample Rate
value for the current iteration
•
minNumPts
:
65536
•
refPosition
:
50.0
•
numRecords
:
1
•
enforceRealtime
:
NISCOPE_VAL_TRUE
5.
Call
niScope_InitiateAcquisition
(niScope Initiate Acquisition VI) with the
following parameter:
•
vi
: The instrument handle you obtained from
niScope_init
6.
Call
niScope_FetchArrayMeasurement
(niScope Fetch Array Measurement VI)
with the following parameters:
•
channelList
:
"0"
•
timeout
:
5.0
•
arrayMeasFunction
:
NISCOPE_VAL_FFT_AMP_SPECTRUM_VOLTS_RMS
•
measWfmSize
:
-1
7.
Calculate the noise value from the returned voltage array V[
n
] using the following formula:
where
i
is obtained from Table 4.
a.
Add up the squares of each element in the returned array starting with element
i
and
ending with element 26,215. The first element in the array is element 0.
b.
Take the square root of the resulting sum. The result is the RMS noise between 100 Hz
and 0.4 ×
Sample Rate
.
Compare the result from this step to the value listed in the
Published Specifications
column in Table 4.
8.
Repeat steps 1 through 7 for each iteration in Table 4.
Noise RMS
V n
2
n
i
=
26215
=