NI 5421/5441 Calibration Procedure
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National
Instruments
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25
Verifying Frequency Response (Flatness)
This test verifies the frequency response (flatness) of the NI 5421/5441 using a power meter.
The flatness verification has two subprocedures that verify the following:
•
Main analog path flatness: low-gain amplifier and high-gain amplifier
•
Direct analog path flatness
Verifying the Main Analog Path Flatness
Complete the following steps to verify the main analog path flatness of the NI 5421/5441.
1.
Connect the NI 5421/5441 CH 0 front panel connector to the power meter using the
required adapter.
2.
Call
niFgen_init
(niFgen Initialize VI) using the following parameters:
•
resourceName
: The name of the device that you want to verify. You can find this
name under Devices and Interfaces in MAX.
•
IDQuery
:
VI_TRUE
•
resetDevice
:
VI_TRUE
•
vi
: A pointer to a ViSession. The variable passed by reference through this parameter
receives the value that identifies the session created by this function. This value acts
as the session handle and is passed as the first parameter to all subsequent NI-FGEN
functions.
3.
Call
niFgenSetAttributeViBoolean
(NI-FGEN Output Enabled property) to disable
the NI 5421/5441 output. Use the following parameters:
•
channelName
:
"0"
•
attributeID
:
NIFGEN_ATTR_OUTPUT_ENABLED
•
value
:
VI_FALSE
•
vi
: The session handle returned from
niFgen_init
4.
Null the power meter according to the power meter documentation.
5.
Configure the power meter using the following settings:
•
Average: 16
•
Measure: Watts
6.
Call
niFgen_SetAttributeViReal64
to set the offset (NI-FGEN Offset property)
using the following parameters:
•
vi
: The session handle returned from
niFgen_init
•
channelName
:
"0"
•
attributeID
:
NIFGEN_ATTR_ARB_OFFSET
•
value
:
0
7.
Call
niFgen_SetAttributeViInt32
to set the main analog path (NI-FGEN Analog
Path property) using the following parameters:
•
vi
: The session handle returned from
niFgen_init
•
channelName
:
"0"
