NI 5421, Процедура калибровки

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NI 5421/5441 Calibration Procedure | © National Instruments | 49
• attributeID :
NIFGEN_ATTR_OUTPUT_IMPEDANCE
• value :
50
9. Call
niFgen_SetAttributeViBoolean
to enable the analog output (NI-FGEN Output
Enabled property) 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 (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 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).
The measured frequency should converge on the desired frequency. If the measured
frequency does not converge on the desired frequency within 16 iterations, a problem may
exist with your measurement device or the NI 5421/5441.
a.
Call
niFgen_AbortGeneration
(niFgen Abort Generation VI) to abort the
waveform generation using the following parameter:
•
vi : The session handle returned from
niFgen_InitExtCal