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National Instruments Corporation
51
NI 5421/5441 Calibration Procedure
9.
Call
niFgen_SetAttributeViBoolean
to enable the analog output
(niFgen property node:
Basic Operation»Output Enabled
) using the
following parameters:
•
vi
: The session handle returned from
niFgen_InitExtCal
•
channelName
:
"0"
•
attributeID
:
NIFGEN_ATTR_OUTPUT_ENABLED
•
value
:
VI_TRUE
10. Generate an array of waveform samples.
Each waveform should have 10 samples per cycle, with a total of
500 samples and 50 sine wave cycles. Because you set the sample rate
to 100 MS/s and because there are 10 samples per cycle, the resulting
waveform is a 10 MHz sine wave.
Note
The sample values of this waveform must fall between –1.0 and 1.0.
11. Call
niFgen_CreateArbWaveform
(niFgen Create Arbitrary
Waveform VI) using the following parameters:
•
vi
: The session handle returned from
niFgen_InitExtCal
•
wfmSize
: The size in samples (
500
) of the waveform you created
in step 10
•
wfmData
: The array of waveform samples that you created in
step 10
•
wfmHandle
: The variable passed by reference through this
parameter receives the value (waveform handle) that identifies
the waveform created by this function.
12. Call
niFgen_SetAttributeViInt32
to choose the sine waveform
(niFgen property node:
Arbitrary Waveform Output»Arbitrary
Waveform Handle
) 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 11 (sine waveform handle)
13. Call
niFgen_InitiateGeneration
(niFgen Initiate Generation VI)
to initiate the waveform generation using the following parameter:
•
vi
: The session handle returned from
niFgen_InitExtCal
14. Measure the frequency of the generated waveform. This value is the
measured frequency
, which is used in step 15.
15. Repeat steps 15a through 15d for as long as the difference between the
measured frequency and the desired frequency (10 MHz) is greater
than the tolerance (4.5 ppm).
