NI 5922 Calibration Procedure
20
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5.
Connect the scope calibrator to the channel 0 input of the digitizer.
Configure the calibrator to output an exact 2 MHz sine wave with 1 V
peak-to-peak amplitude and 50
Ω
load impedance.
6.
Wait 1,000 ms for the impedance matching and frequency of the
calibrator to settle.
7.
Call
niScope_InitiateAcquisition
(niScope Initiate
Acquisition VI) with the following parameter:
•
vi
: The instrument handle you obtained from
niScope_init
8.
Call
niScope_FetchMeasurement
(niScope Fetch
Measurement VI) with the following parameters:
•
channelList
:
"0"
•
timeout
:
1.0
•
scalarMeasFunction
:
NISCOPE_VAL_FFT_FREQUENCY
9.
Calculate the error in timing as parts per million (ppm) using the
following formula:
where
a
= the measured frequency
Compare the result to the
Calibration Test Limits
or the
Published
Specifications
listed in Table 7. If the result is within the selected test
limit, the device has passed this portion of the verification.
Flatness
Complete the following steps to verify the flatness of the NI 5922. You
must verify both channels and each iteration listed in Table 8.
1.
Call
niScope_ConfigureChanCharacteristics
(niScope
Configure Chan Characteristics VI) with the following parameters:
•
channelList
:
"0"
•
inputImpedance
:
NISCOPE_VAL_50_OHM
•
maxInputFrequency
:
0
Table 7.
NI 5922 Timing Accuracy
Calibration Test Limi
Published Specification
±5.3 ppm
±50 ppm
error
a
2,000,000
–
(
)
2
-------------------------------------
=
