National Instruments PXIe-5622 Manual

CALIBRATION PROCEDURE
NI 5622
This document contains instructions for writing an external calibration
procedure for National Instruments PXIe-5622 digitizers. This calibration
procedure is intended for metrology labs. For more information about
calibration, visit ni.com/calibration.
Contents
Conventions ............................................................................................ 2
Software Requirements ........................................................................... 3
Documentation Requirements................................................................. 4
Password ................................................................................................. 5
Calibration Interval ................................................................................. 5
External Calibration ......................................................................... 5
Self-Calibration................................................................................ 5
Test Equipment ....................................................................................... 5
Test Conditions ....................................................................................... 7
Calibration Procedures ............................................................................ 8
Initial Setup...................................................................................... 9
Self-Calibration................................................................................ 9
MAX......................................................................................... 9
NI-SCOPE SFP......................................................................... 9
NI-SCOPE ................................................................................ 10
Test Equipment Adjustment ............................................................ 11
Zero Power Meter..................................................................... 11
Power Splitter Amplitude Imbalance Correction ..................... 11
Verification ...................................................................................... 14
Absolute Amplitude Accuracy ................................................. 14
Bandpass Amplitude Flatness................................................... 21
Timing Accuracy ...................................................................... 30
SSB Phase Noise ...................................................................... 34
Average Noise Density............................................................. 42
Adjustment....................................................................................... 46
Appendix A: Calibration Utilities ........................................................... 51
MAX ................................................................................................ 51
NI-SCOPE ....................................................................................... 52
Where to Go for Support......................................................................... 52

NI 5622 Calibration Procedure 2 ni.com
Conventions
The following conventions are used in this document:
»The »symbol leads you through nested menu items and dialog box options
to a final action. The sequence Options»Settings»General directs you to
pull down the Options menu, select the Settings item, and select General
from the last dialog box.
This icon denotes a note, which alerts you to important information.
This icon denotes a caution, which advises you of precautions to take to
avoid injury, data loss, or a system crash.
bold Bold text denotes items that you must select or click in the software, such
as menu items and dialog box options. Bold text also denotes parameter
names.
italic Italic text denotes variables, emphasis, a cross-reference, or an introduction
to a key concept. Italic text also denotes text that is a placeholder for a word
or value that you must supply.
monospace Text in this font denotes text or characters that you should enter from the
keyboard, sections of code, programming examples, and syntax examples.
This font is also used for the proper names of disk drives, paths, directories,
programs, subprograms, subroutines, device names, functions, operations,
variables, filenames, and extensions.
Platform Text in this font denotes a specific platform and indicates that the text
following it applies only to that platform.

©National Instruments Corporation 3 NI 5622 Calibration Procedure
Software Requirements
Calibrating the NI 5622 requires installing the following software on the
calibration system.
You can download NI-SCOPE from the National Instruments web site at
ni.com/updates. NI-SCOPE supports programming the
Self-Calibration and Verification sections in a number of programming
languages; however, only LabVIEW and C are supported for the
Adjustment section.
NI-SCOPE includes all the functions and attributes necessary
for calibrating the NI 5622. LabVIEW support is installed in
niScopeCal.llb, and all calibration functions appear in the function
palette. For LabWindows™/CVI™, the NI-SCOPE function panel
niScopeCal.fp provides further help on the functions available in CVI.
Refer to Table 2 for installed file locations.
Calibration functions are LabVIEW VIs or C function calls in the
NI-SCOPE driver. The C function calls are valid for any compiler capable
of calling a 32-bit DLL. Many of the functions use constants defined in
the niScopeCal.h file. To use these constants in C, you must include
niScopeCal.h in your code when you write the calibration procedure.
For more information on the calibration VIs and functions, refer to the
NI-SCOPE LabVIEW Reference Help or the NI-SCOPE Function
Reference Help. These references can be found in the NI High-Speed
Digitizers Help. Refer to the NI-SCOPE Readme for the installed locations
of these documents.
Table 1. Required Software Specifications for NI 5622 Calibration
LabVIEW LabWindows/CVI and C/C++
NI-SCOPE 3.5 or later NI-SCOPE 3.5 or later
NI LabVIEW Digital Filter
Design Toolkit 8.2.1 or later
NI Modulation Toolkit for
LabWindows/CVI 2.0 or later
NI Modulation Toolkit for
LabVIEW 3.0 or later —

NI 5622 Calibration Procedure 4 ni.com
Documentation Requirements
You may find the following documentation helpful as you write your
calibration procedure:
• NI High-Speed Digitizers Getting Started Guide
• NI High-Speed Digitizers Help
–NI-SCOPE LabVIEW Reference Help (NI-SCOPE VIs and
NI-SCOPE Properties)
–NI-SCOPE Function Reference Help
• NI PXIe-5622 Specifications
These documents are installed with NI-SCOPE. You can also download
the latest versions from ni.com/manuals.
Table 2. Calibration File Locations after Installing NI-SCOPE
File Name and Location Description
IVI\Bin\niscope_32.dll NI-SCOPE driver containing the entire
NI-SCOPE API, including calibration functions
IVI\Lib\msc\niscope.lib NI-SCOPE library for Microsoft C containing
the entire NI-SCOPE API, including calibration
functions
<LabVIEW> \examples\instr\niScope Directory of LabVIEW NI-SCOPE example
VIs, including self-calibration.
<LabVIEW> \instr.lib\niScope\
Calibrate\niScopeCal.llb
LabVIEW VI library containing VIs for calling
the NI-SCOPE calibration API.
IVI\Drivers\niScope\niScopeCal.fp CVI function panel file that includes external
calibration function prototypes and information
about using NI-SCOPE in the CVI environment.
IVI\Include\niScopeCal.h Calibration header file, which you must include
in any C program accessing calibration
functions. This file automatically includes
niScope.h, which defines the rest of the
NI-SCOPE interface.
IVI\Drivers\niScope\Examples Directory of NI-SCOPE examples for CVI, C,
Visual C++, and Visual Basic.

©National Instruments Corporation 5 NI 5622 Calibration Procedure
Password
A password is required to open an external calibration session. If the
password has not been changed since manufacturing, the password is NI.
Calibration Interval
External Calibration
The measurement accuracy requirements of your application determine
how often you should externally calibrate the NI 5622. NI recommends
that you perform a complete external calibration at least once every year.
You can shorten this interval based on the accuracy demands of your
application.
Self-Calibration
You can perform self-calibration whenever necessary to compensate for
environmental changes.
Caution Although you can repeatedly self-calibrate, self-calibrating the NI 5622 more
than a few times a day may cause excessive wear on the relays over time.
Test Equipment
Table 3 lists the equipment required for externally calibrating the NI 5622.
If you do not have the recommended instruments, use these specifications
to select a substitute calibration standard.

NI 5622 Calibration Procedure 6 ni.com
Table 3. Required Equipment Specifications for NI 5622 External Calibration
Required
Equipment
Recommended
Equipment
Calibration
Procedure Specification
Signal
Generator
Rohde and
Schwarz
SMA-B103 with
SMA-B22 option,
enhanced phase
noise performance
SSB Phase
Noise Carrier
Frequency
Carrier Offset
100 Hz 1 kHz 10 kHz
53 MHz –108
dBc/Hz
–146
dBc/
Hz
–158
dBc/
Hz
187 MHz –98
dBc/Hz
–135
dBc/
Hz
–148
dBc/
Hz
Bandpass
Amplitude
Flatness,
Absolute
Amplitude
Accuracy,
SSB Phase
Noise, Timing
Accuracy,
Adjustment
Frequency Range: 900 kHz to 820 MHz
Power Measurement Level Setting Range:
–4 dBm to 10 dBm
Timing
Accuracy,
Adjustment
±0.1 ppm frequency accuracy
Power
Meter
Rohde and
Schwarz
NRP-Z91 with
NRP-Z4 USB
adapter
Absolute
Amplitude
Accuracy,
Bandpass
Amplitude
Flatness,
Adjustment
Frequency Range:
900 kHz to 820 MHz
Power Measurement Range:
–4 dBm to 3 dBm
Maximum VSWR:
1.11 (23 ±5 °C)
Absolute Power Measurement Uncertainty:
0.1 dB (23 ±5 °C)
Relative Power Measurement Uncertainty:
0.05 dB (23 ±5 °C)

©National Instruments Corporation 7 NI 5622 Calibration Procedure
Test Conditions
Follow these guidelines to optimize the connections and the environment
during calibration:
• Keep cables as short as possible. Long cables act as antennae, picking
up noise that can affect measurements.
• Verify that all connections, including front panel connections, are
secure.
SMA Cable Mini-Circuits
CBL-1.5FT-SMS
M+
Bandpass
Amplitude
Flatness,
Absolute
Amplitude
Accuracy,
SSB Phase
Noise, Timing
Accuracy,
Adjustment
50 Ω, Maximum VSWR: 1.20
Frequency Range: 900 kHz to 820 MHz
Power Measurement Range:
–4 dBm to 3 dBm
Relative Shielding: –100 dB
Attenuator Mini-Circuits
VAT- 3 +
SSB Phase
Noise
Frequency Range: 900 kHz to 820 MHz
Minimum Power (W): 10 mW
Maximum VSWR: 1.20
Nominal Attenuation: 3 dB
SMA
Termination
Mini-Circuits
ANNE-50+
Average
Noise Density
50 Ω
Power
Splitter
Weinschel
WA1507R
Absolute
Amplitude
Accuracy,
Bandpass
Amplitude
Flatness,
Adjustment
Frequency Range: 900 kHz to 820 MHz
Input Power Range: –4 dBm to 3 dBm
Maximum VSWR (Output ports): 1.15
Maximum Amplitude Tracking: 0.15 dBm
Table 3. Required Equipment Specifications for NI 5622 External Calibration (Continued)
Required
Equipment
Recommended
Equipment
Calibration
Procedure Specification

NI 5622 Calibration Procedure 8 ni.com
• Ensure that the PXIe chassis fan speed is set to HIGH, that the fan
filters are clean, and that the empty slots contain filler panels. For more
information, refer to the Maintain Forced-Air Cooling Note to Users,
available at ni.com/manuals.
• Keep relative humidity between 10% and 90% noncondensing, or
consult the NI PXIe-5622 Specifications for the optimum relative
humidity.
• Maintain an ambient temperature of 23 ±5 °C.
• Allow a warm-up time of at least 15 minutes after the NI-SCOPE
driver is loaded. Unless manually disabled, NI-SCOPE automatically
loads with the operating system and enables the device. The warm-up
time ensures that the measurement circuitry of the digitizer is at a
stable operating temperature.
• Plug the PXI Express chassis and the test equipment into the same
power strip to avoid ground loops.
Calibration Procedures
The calibration process includes the following steps.
1. Initial Setup—Install the device and configure it in Measurement &
Automation Explorer (MAX).
Note Allow a 15-minute warm-up time before beginning self-calibration.
2. Self-Calibration—Adjust the self-calibration constants of the device.
3. Test Equipment Adjustment—Zero the power meter and calculate
power splitter imbalance.
4. Verification—Verify the existing operation of the device. This step
confirms whether the device is operating within its specified range
prior to calibration.
5. Adjustment—Perform an external adjustment of the device that adjusts
the calibration constants with respect to a known voltage source. The
adjustment procedure automatically stores the calibration date on the
EEPROM to allow traceability.
6. Reverification—Repeat the verification procedure to ensure that the
device is operating within its specifications after adjustment.
These steps are described in more detail in the following sections.

©National Instruments Corporation 9 NI 5622 Calibration Procedure
Initial Setup
Refer to the NI High-Speed Digitizers Getting Started Guide for
information about how to install the software and hardware and how
to configure the device in MAX.
Self-Calibration
The NI 5622 includes precise internal circuits and references used during
self-calibration to adjust for time and temperature drift.
Note Allow a 15 minute warm-up period before you begin self-calibration.
Note Always self-calibrate the digitizer before you perform verification. NI-SCOPE
includes self-calibration example programs for LabVIEW, CVI, and Microsoft Visual C.
You can initiate self-calibration using the following methods:
•MAX
• NI-SCOPE Soft Front Panel (SFP)
•NI-SCOPE
MAX
To initiate self-calibration from MAX, complete the following steps:
1. Disconnect or disable any AC inputs to the digitizer.
2. Launch MAX.
3. Expand My System»Devices and Interfaces»PXI System.
4. Select the device that you want to calibrate.
5. Initiate self-calibration using one of the following methods:
•ClickSelf-Calibrate in the upper right corner of MAX.
• Right-click the name of the device in the MAX configuration tree
and select Self-Calibrate from the drop-down menu.
NI-SCOPE SFP
To initiate self-calibration from the NI-SCOPE SFP, complete the
following steps:
1. Disconnect or disable any AC inputs to the digitizer.
2. Launch the NI-SCOPE SFP, which is available at Start»All Programs»
National Instruments»NI-SCOPE»SCOPE Soft Front Panel.
3. Select the device you want to calibrate using the Device Configuration
dialog box by selecting Edit»Device Configuration.

NI 5622 Calibration Procedure 10 ni.com
4. Launch the Calibration dialog box by selecting Utility»
Self Calibration.
5. Click OK to begin self-calibration.
NI-SCOPE
To self-calibrate the NI 5622 programmatically using NI-SCOPE,
complete the following steps:
1. Disconnect or disable any AC inputs to the digitizer.
Note Throughout the procedure, refer to the C/C++ function call parameters for the
LabVIEW input values.
2. Open a session and obtain a session handle using the niScope
Initialize VI.
3. Self-calibrate the digitizer using niScope Cal Self Calibrate VI.
Note Because the session is a standard session rather than an external calibration session,
the new calibration constants are immediately stored in the EEPROM. Therefore, you can
include this procedure in any application that uses the digitizer.
LabVIEW VI C/C++ Function Call
Call niScope_init with the following
parameters:
vi: The returned session handle that you use to
identify the instrument in all subsequent
NI-SCOPE driver function calls
resourceName: The device name assigned by
MAX
idQuery: VI_FALSE
resetDevice: VI_TRUE
LabVIEW VI C/C++ Function Call
Call niScope_CalSelfCalibrate with
the following parameters:
sessionHandle: The instrument handle from
niScope_init
channelList: VI_NULL
option: VI_NULL

©National Instruments Corporation 11 NI 5622 Calibration Procedure
4. End the session using the niScope Close VI.
Test Equipment Adjustment
Zero Power Meter
Zero the power meter by following the manufacturer’s recommended
procedure.
Power Splitter Amplitude Imbalance Correction
Complete the following steps to determine the power splitter amplitude
imbalance correction factor used to verify and adjust the NI 5622.
1. Make the following connections:
a. Connect the signal generator to the source input port of the power
splitter.
b. Connect the power meter to output port 1 of the power splitter.
c. Connect the 50 ohm terminator to output port 2 of the power
splitter.
LabVIEW VI C/C++ Function Call
Call niScope_close with the following
parameter:
vi: The instrument handle from niScope_init

NI 5622 Calibration Procedure 12 ni.com
Figure 1. Initial Connections for Power Splitter Amplitude Imbalance Correction
2. Configure the signal generator to generate a 100 MHz, 0.6325 Vpk-pk
sine wave.
3. Wait the amount of time the manufacturer recommends for the output
to settle.
4. Measure the power (in watts) of the sine wave using the power meter.
This value is the Measured Sine Wave Power of Port 1 used in step 7.
5. Make the following connection changes:
a. Connect the power meter to input port 2 of the power splitter.
b. Connect the 50 Ωterminator to input port 1 of the power splitter.
1 R&S NRP-Z91 Power Meter
2 Weinschel WA 1507R Splitter
3 50 ΩTermination
4 To Signal Generator
2
S
1
1
2
4
3

©National Instruments Corporation 13 NI 5622 Calibration Procedure
Figure 2. Connection Changes for Power Splitter Amplitude Imbalance Correction
6. Measure the power (in watts) of the sine wave using the power meter.
This value is the Measured Sine Wave Power of Port 2 used in step 7.
7. Calculate the amplitude imbalance between the two output ports of the
power splitter using the following formula:
Splitter Power Correction
where
a = Measured Sine Wave Power of Port 1
b= Measured Sine Wave Power of Port 2
The Splitter Power Correction (in dB) is used in the Absolute
Amplitude Accuracy, and Adjustment sections of this document.
Note Make note of which output port of the power splitter is port 1 and which is port 2.
Refer to the power splitter documentation for information on port designations. Reversing
the connection in the adjustment and verification steps may invalidate the calibration of the
NI 5622.
1 50 ΩTermination
2 Weinschel WA 1507R Splitter
3 To Signal Generator
4 R&S NRP-Z91 Power Meter
2
S
1
4
1
3
2
10 log10 ×b
a
---


=

NI 5622 Calibration Procedure 14 ni.com
Verification
This section describes the program you must write to verify the
performance of the NI 5622 to the published specifications for the device.
Note If any of these tests fail immediately after you perform an external adjustment, make
sure that you have met the requirements listed in the Test Equipment and Test Conditions
sections before you return the digitizer to National Instruments for repair.
Absolute Amplitude Accuracy
Complete the following steps to verify the absolute amplitude accuracy of
the NI 5622.
1. Make the following connections:
a. Connect the signal generator to the source input port of the power
splitter using the SMA cable.
b. Connect the power meter to output port 1 of the of the power
splitter.
c. Connect channel 0 (IF IN) of the digitizer to output port 2 of the
power splitter.
Figure 3. NI 5622 Absolute Amplitude Accuracy Connections
1 R&S NRP-Z91 Power Meter
2 Weinschel WA 1507R Splitter
3 To Signal Generator
NI PXIe-5622
16-Bit IF Digitizer
ACCESS AC TIVE
PFI 1
IF IN
CLK IN
CLK OUT
TTL (+5 V MAX)
2
S
1
3
21

©National Instruments Corporation 15 NI 5622 Calibration Procedure
2. Open a session and obtain a session handle using the niScope
Initialize VI.
3. Configure the input impedance and the maximum input frequency
using the niScope Configure Chan Characteristics VI.
4. Configure the common vertical properties using the niScope Configure
Vertical VI.
LabVIEW VI C/C++ Function Call
Call niScope_init with the following
parameters:
resourceName: The device name assigned by
MAX
idQuery: VI_FALSE
resetDevice: VI_TRUE
LabVIEW VI C/C++ Function Call
Call niScope_ConfigureChan
Characteristics with the following
parameters:
vi: The instrument handle from
niScope_init
channelList: “0”
inputImpedance: NISCOPE_VAL_50_OHM
maxInputFrequency: 250,000,000
LabVIEW VI C/C++ Function Call
Call niScope_ConfigureVertical
with the following parameters:
vi: The instrument handle from
niScope_init
channelList: “0”
range: The Range value listed in Table 4
for the current iteration
offset: 0.0
coupling: NISCOPE_VAL_AC
probeAttenuation: 1.0
enabled: NISCOPE_VAL_TRUE

NI 5622 Calibration Procedure 16 ni.com
5. Configure the horizontal properties using the niScope Configure
Horizontal Timing VI.
6. Configure the bandpass filter using the niScope Property Node.
7. Commit all the parameter settings to hardware using the niScope
Commit VI.
LabVIEW VI C/C++ Function Call
Call niScope_Configure
HorizontalTiming with the
following parameters:
vi: The instrument handle from
niScope_init
enforceRealtime:
NISCOPE_VAL_TRUE
numRecords: 1
minSampleRate: 150,000,000
refPosition: 0.0
minNumPts: 524,288
LabVIEW VI C/C++ Function Call
Call niScope_SetAttributeViBoolean with
the following parameters:
vi: The instrument handle from niScope_init
channelList: “0”
attributeId:
NISCOPE_ATTR_BANDPASS_FILTER_ENABLED
value: The Bandpass Filter value listed in
Table 4 for the current iteration
LabVIEW VI C/C++ Function Call
Call niScope_Commit with the following
parameter:
vi: The instrument handle from
niScope_init

©National Instruments Corporation 17 NI 5622 Calibration Procedure
8. This step varies depending on the programming language used.
(LabVIEW) Configure the frequency response compensation using the Apply
Frequency Response Compensation VI. The value returned is the
Reference Flatness Gain Correction Factor used in step 15.
Note You can download the Apply Frequency Response Compensation VI from the
NI Web site at ni.com/info. Use the Info Code ex6vhg.
(C/C++) Configure the custom coefficients for the equalization FIR filter of
the digitizer. Use the following function and attribute calls
to calculate the customer coefficients.
a. To get the frequency response of the digitizer, call
niScope_GetFrequencyResponse.
b. To get the number of coefficients the FIR filter can accept, call the
NISCOPE_ATTR_EQUALIZATION_NUM_COEFFICIENTS
attribute.
c. To configure the custom coefficients for the FIR filter, call
niScope_ConfigureEqualizationFilterCoefficients.
9. Configure the signal generator to generate an Input Frequency, Input
Voltage sine wave for the current iteration in Table 4.
10. Wait the amount of time the manufacturer recommends for the output
to settle.
11. Measure the power (in watts) of the sine wave using the power meter.
This value is the Power Meter Measured Sine Wave Power used in
step 15.
LabVIEW VI Input Parameters
Set the following parameters:
bandwidth: –1
center frequency: The Reference
Frequency value in Table 4 for the
current iteration
channel: “0”
apply flatness: TRUE
cache: FALSE

NI 5622 Calibration Procedure 18 ni.com
12. Initiate a waveform acquisition using the niScope Initiate
Acquisition VI.
13. Acquire a waveform using the niScope Fetch (poly) VI. Select the
WDT instance of the VI. Use the default value for the timestamp Type
parameter.
14. This step varies depending on the programming language used.
(LabVIEW) Measure the peak voltage of the sine wave being generated using
the Extract Single Tone Information VI. This value is the Digitizer
Measured Sine Wave Amplitude used in step 15.
(C/C++) Perform an FFT on the array of data from step 13.
LabVIEW VI C/C++ Function Call
Call niScope_Initiate
Acquisition with the following
parameter:
vi: The instrument handle from
niScope_init
LabVIEW VI C/C++ Function Call
Call niScope_Fetch with the following
parameters:
vi: The instrument handle from
niScope_init
channelList: “0”
timeout: 5.0
numSamples: –1
LabVIEW Block Diagram Input Parameters
Set the following parameters:
advanced search»approx freq.: –1
advanced search»search: 5
export signals: 0(none)

©National Instruments Corporation 19 NI 5622 Calibration Procedure
15. Calculate the absolute amplitude accuracy error using the following
formula:
where
a= Digitizer Measured Sine Wave Amplitude
b= Reference Flatness Gain Correction Factor
c = Power Meter Measured Sine Wave Power
d= Splitter Power Correction
Compare the result to the Published Specifications for the current
iteration listed in Table 4. If the results are within the selected test
limit, the device has passed this portion of the verification.
16. Repeat steps 4 through 15 for each iteration in Table 4.
17. End the session using the niScope Close VI.
You have finished verifying the absolute amplitude accuracy for the
NI 5622.
LabVIEW VI C/C++ Function Call
Call niScope_close with the following para
meter:
vi: The instrument handle from
niScope_init
error 10 log10 ×ab×()
2
c
-------------------


20–d+=

NI 5622 Calibration Procedure 20 ni.com
Table 4. NI 5622 Absolute Amplitude Accuracy Specifications Limits
Iteration Range (Vpk-pk)Bandpass Filter
Input Voltage
(Vpk-pk)
Reference
Frequency (MHz)
Specifications Limits
Max Level (dB) Min Level (dB)
10.7 NISCOPE
_VAL_
FALSE
0.35 53 0.4 –0.4
21.05
3 1 0.5 0.4 –0.4
41.5
51.4 0.7 0.4 –0.4
62.1
70.7 NISCOPE
VAL
_TRUE
0.35 187.55 0.5 –0.5
81.05
9 1 0.5 0.5 –0.5
10 1.5
11 1.4 0.7 0.5 –0.5
12 2.1