NI 5421, Calibration Procedure

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NI 5421/5441 Calibration Procedure | © National Instruments | 31
• wfmHandle : A pointer to a waveform. The variable passed by reference through this
parameter acts as a handle to the waveform and can be used for setting the active
waveform, changing the data in the waveform, building sequences of waveforms, or
deleting the waveform when it is no longer needed.
14. Call
niFgen_SetAttributeViInt32
(NI-FGEN Arbitrary Waveform Handle
property) using the following parameters:
•
vi : The session handle returned from
niFgen_init
• channelName :
"0"
• attributeID :
NIFGEN_ATTR_ARB_WAVEFORM_HANDLE
• value : The wfmHandle from step 13
a. Call
niFgen_SetAttributeViBoolean
to set the digital filter state (NI-FGEN
Digital Filter Enabled property) using the following parameters:
•
vi : The session handle returned from
niFgen_InitExtCal
• channelName :
"0"
• attributeID :
NIFGEN_ATTR_DIGITAL_FILTER_ENABLED
• value :
VI_TRUE
b. Call
niFgen_SetAttributeViReal64
to set the digital filter interpolation factor
(NI-FGEN Digital Filter Interpolation Factor property) using the following
parameters:
•
vi : The session handle returned from
niFgen_InitExtCal
• channelName :
"0"
• attributeID :
NIFGEN_ATTR_DIGITAL_FILTER_INTERPOLATION_FACTOR
• value :
4
15. Call
niFgen_InitiateGeneration
(niFgen Initiate Generation VI) using the
following parameter:
•
vi : The session handle returned from
niFgen_init
16. Allow the power meter to stabilize for 10 seconds.
17. Measure and record the power (
W
f
) of the positive output in Watts. Use the recorded power
at 50 kHz as reference power ( W
ref
).
18. Call
niFgen_AbortGeneration
(niFgen Abort Generation VI) to abort the current
generation using the following parameter:
•
vi : The session handle returned from
niFgen_init
19. For iterations 2-11 in Table 9, using the recorded power values, calculate the deviation from
the reference (50 kHz) power using the following equation:
20. Compare the Flatness (dB) values calculated in step 19 to the Published Specification listed
in Table 9.
Flatness dB
 
10
W
f
W
ref
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log
=