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NI PXI-5404 Calibration Procedure
|
© National Instruments
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11
•
ID Query
—
True
•
Reset Device
—
True
2.
Call
niFgen_ConfigureStandardWaveform()
to configure the sine wave. Set the
following parameters:
•
vi
—The output that is passed in by reference to the verification functions as
sessionHandle
•
Channel_Name
—
"0"
•
Amplitude
—
2
•
Start phase
—
0
•
Frequency
—
50000
•
DC offset
—
0
•
Waveform
—
NIFGEN_VAL_WFM_SINE
3.
Call
niFgen_InitiateGeneration()
. This function causes the NI 5404 to leave its
configuration state and enter its signal generation state. Set the following parameter:
•
vi
—The output value
sessionHandle
you obtained from the
niFgen_init
function
4.
Measure the SINE out amplitude using a DMM specified in Table 1.
Note
The 50 kHz amplitude accuracy of the DMM is better than the 50 kHz
amplitude accuracy of the power meter. To get the best passband flatness results, you
either must calibrate the power meter or use the power meter to make amplitude
measurements, at frequency indices 0-11, which are relative to the absolute
amplitude measurement made by the DMM at frequency index 0. The latter choice is
preferred.
To measure the SINE out amplitude passband flatness using the power meter, complete the
following steps:
a.
Measure the 50 kHz amplitude using the AC rms (dBm) function of the DMM. Do not
use a 50
Ω
terminator when using the DMM.
b.
Subtract 6 dBm from the DMM measurement, because the power meter has a 50
Ω
input impedance. The result of the subtraction is the power level of the 50 kHz SINE
out into a 50
Ω
load.
c.
Measure the 50 kHz amplitude with the power meter and compare the power result to
the DMM result. If the power meter result is higher than the DMM result, subtract the
difference of the two results (in dBm) from the power meter results for frequency
indexes 0 to 11. If the power meter result is lower than the DMM result, add the
difference of the two results (in dBm) to the power meter results for frequency indexes
0 to 11.
5.
Disconnect the SINE out of the NI 5404 from the DMM and connect SINE out to the power
meter using the SMB to N-Type cable.