NI PXI-5404 Calibration Procedure
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© National Instruments
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2.
Connect the SINE out to the appropriate instrument, which is determined by the frequency
in Table 5.
3.
Generate a waveform at each frequency listed in Table 5.
For the first iteration of the steps, use the DMM as the measurement device; for the
remaining iterations of the steps, use the power meter as the measurement device.
Steps 3a through 3c explain how to use the power meter for amplitude measurements.
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 1-20, which are relative to the absolute
amplitude measurement made by the DMM at frequency index 0. The latter choice is
preferred.
To implement using the power meter to make amplitude measurements, 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 from the power meter results (in dBm) for frequency
indexes 1 to 20. 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
1 to 20.
Repeat step 3d for each frequency listed in Table 5. To generate the waveforms, complete
the following steps:
d.
Repeat the following steps to generate a waveform for each frequency:
1.
Call
niHSSources_GenerateWaveform
(niHSSources Cal
GenerateWaveform VI). This function generates a sine wave at the current
frequency. Set the following parameters:
•
sessionHandle
—The handle of the calibration session for the module
•
waveform Type
—
niHSSources_SINE
•
amplitude In Volts
—
2.0
•
frequencies
—The frequency listed in Table 5 for the current index
2.
Enable the output by calling
niHSSources_SetArbOutput
(niHSSources
Cal SetArbOutputVI). Set the following parameters:
•
sessionHandle
—The handle of the calibration session for the module
•
outputState
—
niHSSources_ENABLE