National Instruments NI-5761 User manual

NI-5761

NI 5761R User Guide and Specifications
The NI 5761 is a 250 MS/s analog input adapter module designed to work in conjunction with your
NI FlexRIO™FPGA module. This document contains signal information and specifications for the
NI 5761R, which is comprised of an NI FlexRIO FPGA module and the NI 5761. This document also
contains tutorial sections that demonstrate how to acquire data using a LabVIEW FPGA example VI
and how to create and run your own LabVIEW project with the NI 5761R.
Contents
Front Panel and Connector Pinouts ..................................................................................................... 2
Block Diagram ..................................................................................................................................... 4
NI 5761 Component-Level Intellectual Property (CLIP) .................................................................... 5
Cables................................................................................................................................................... 6
Clocking............................................................................................................................................... 7
Using Your NI 5761R with a LabVIEW FPGA Example VI.............................................................. 7
Creating a LabVIEW Project and Run a VI on an FPGA Target ........................................................ 9
How to Use Your NI FlexRIO Documentation Set ............................................................................. 12
Specifications....................................................................................................................................... 13
Where to Go for Support ..................................................................................................................... 24
Note Before configuring your NI 5761R, you must install the appropriate software and hardware.
Refer to the NI FlexRIO FPGA Module Installation Guide and Specifications for installation
instructions. Figure 1 shows an example of a properly connected NI FlexRIO device.
Figure 1. NI FlexRIO Device
NI FlexRIO
Adapter Module + = NI FlexRIO Device
NI FlexRIO
FPGA Module

NI 5761R User Guide and Specifications 2 ni.com
Front Panel and Connector Pinouts
Front Panel
Table 1 shows the front panel connector and signal descriptions for the NI 5761. Refer to the
Specifications section of this document for additional signal information.
Caution To avoid permanent damage to the NI 5761, disconnect all signals connected to the NI 5761
before powering down the module, and only connect signals after the adapter module has been
powered on by the NI FlexRIO FPGA module.
Table 1. NI 5761 Front Panel Connectors
Device Front Panel Connector Signal Description
AUX I/O Refer to Table 2 for the signal names and descriptions.
D<0..3> LEDs for custom configuration.
CLK IN Provides the NI 5761 with an external Sample clock or
Reference clock.
TRIG Trigger input channel.
CH 0 Analog input channels <0..3>.
CH 1
CH 2
CH 3
NI 5761NI 5761
250 MS/s
Analog Input
D0 D1 D2 D3
CLK IN TRIG CH 0 CH 1 CH 2 CH 3
AUX I/O

©National Instruments Corporation 3 NI 5761R User Guide and Specifications
AUX I/O Connector
Table 2 shows the pins assignments for the AUX I/O connector on the NI 5761.
Caution Connections that exceed any of the maximum ratings of any connector on the NI 5761R
can damage the device and the chassis. NI is not liable for any damage resulting from such signal
connections. For the maximum input and output ratings for each signal, refer to the Specifications
section of this document.
Table 2. NI 5761 AUX I/O Connector Pin Assignments
Micro-D Connector Pin Signal Signal Description
1 AUXIO0 General-purpose digital input or output channels.
2 AUXIO1
3 AUXIO2
4 AUXIO3
5 AUXIO4
6 AUXIO5
7 AUXIO6
8 AUXIO7
9 GND Ground.
10 GND
11 GND
12 GND
13 GND
14 GND
15 GND
9
10
11
12
13
14
15
1
2
3
4
5
6
7
8

NI 5761R User Guide and Specifications 4 ni.com
Block Diagram
Figure 2 shows the NI 5761 block diagram and signal flow to and from the NI 5761 component-level intellectual
property (CLIP) by way of the adapter module and the corresponding NI 5761 CLIP in LabVIEW FPGA.
Figure 2. NI 5761 Connector Signals and NI 5761 CLIP Signal Block Diagram
PFI Input
LabVIEW FPGA CLIPNI 5761 Adapter Module
PFI Output
PFI Write Enable
PFI Connector
Enable
LED <0..3>
Trigger Input
SPI Read
SPI Write
SPI Address
SPI Write Data
SPI Read Data
SPI Device Select
Initialization Done
Reinitialize
Configuration Error
Sample Clock Select
Sample Clock Commit
SPI Idle
Analog FE
IO Module Clock 0
(n = 1, Single Sample CLIP
n = 2, Multiple Sample CLIP)
Multiple
Sample CLIP
Single
Sample CLIP
AI 0
AI 1
AI 2
AI 3
AI 0 Data N
AI 1 Data N
AI 2 Data N
AI 3 Data N
AI 0 Data N–1
AI 1 Data N–1
AI 2 Data N–1
AI 3 Data N–1
Data
Clock
Data
Sample Clock
Clock
Buffer
Internal
Reference
Clock
Clock
Synthesizer
Switch
Buffer
Switch
CLK IN
D<0..3>
(LEDs)
AUX I/O
TRIG
CH 0
CH 1
CH 2
CH 3
Switch
Clock
ADC
Interface
IOModSyncClock
1/n
Switches
ADS62P49
ADS62P49
ADS62P49
Analog
Front End
FET
Buffer
FET
Buffer
8
8
8
8
4
Analog
Front End
Analog
Front End
Analog
Front End
AD9512
AD9512
SPI Engine
Interfacing
with:
Synthesizer Locked

©National Instruments Corporation 5 NI 5761R User Guide and Specifications
NI 5761 Component-Level Intellectual Property (CLIP)
The LabVIEW FPGA Module includes a feature for HDL IP integration called CLIP. NI FlexRIO
devices support two types of CLIP: user-defined and socketed.
•User-defined CLIP allows users to insert HDL IP into an FPGA target, enabling VHDL code to
communicate directly with an FPGA VI.
•Socketed CLIP provides the same IP integration functionality of the user-defined CLIP, but also
allows the CLIP to communicate directly with circuitry external to the FPGA. Adapter module
socketed CLIP allows your IP to communicate directly with both the FPGA VI and the external
adapter module connector interface.
Figure 3 shows the relationship between an FPGA VI and CLIP.
Figure 3. CLIP Relationship
Adapter Module
CLIP Socket
LabVIEW
FPGA VI
User-Defined
CLIP
NI FlexRIO FPGA Module
FPGA
External
I/O Connector
Adapter
Module
Socketed
CLIP
User-Defined
CLIP Fixed I/O
DRAM 0
CLIP Socket
Socketed
CLIP
DRAM 1
CLIP Socket
Socketed
CLIP
Fixed I/O Fixed I/O
DRAM0 DRAM1

NI 5761R User Guide and Specifications 6 ni.com
The NI 5761 ships with socketed CLIP items that are used to add module I/O to the LabVIEW project.
The NI 5761 ships with the following CLIP items:
•NI 5761 Multiple Sample CLIP—Generates two samples per clock cycle at a clock rate that is
half the sample rate. The default sample rate is 250 MHz, which sets the default clock rate for this
CLIP at 125 MHz. You can set a lower sample rate by using an external Sample clock. This CLIP
provides access to four analog input channels, eight PFI lines, and an input clock selector that can
be configured to use one of the following settings:
– Internal Sample clock
– Internal Sample clock locked to an external Reference clock through the CLK IN connector
– External Sample clock through the CLK IN connector
– Internal Sample clock locked to an external Reference clock through IoModSyncClock
– External Sample clock through IoModSyncClock
This CLIP also contains an engine to program the CLK chip and ADCs, either through predetermined
settings for an easier instrument setup or through a raw SPI address and data signals for a more advanced
setup. The NI 5761 Multiple Sample CLIP is the default CLIP.
•NI 5761 Single Sample CLIP—Generates one sample per clock cycle at a default sample rate of
250 MHz. You can set a lower sample rate by using an external Sample clock. This CLIP provides
access to four analog input channels, eight PFI lines, and an input clock selector that can be
configured to use one of the following settings:
– Internal Sample clock
– Internal Sample clock locked to an external Reference clock through the CLK IN connector
– External Sample clock through the CLK IN connector
– Internal Sample clock locked to an external Reference clock through IoModSyncClock
– External Sample clock through IoModSyncClock
This CLIP also contains an engine to program the CLK chip and ADCs, either through predetermined
settings for an easier instrument setup or through a raw SPI address and data signals for a more advanced
setup.
Refer to the NI FlexRIO Help in the LabVIEW Help for more information about NI FlexRIO CLIP items,
configuring the NI 5761 with a socketed CLIP, and a list of available socketed CLIP and provided
signals.
Cables
Use the NI CMD-to-CMD cable (NI part number 763194-01) or the NI CMD Single-ended to Pigtail
cable (NI part number 763191-01) to connect signals to your AUX I/O connector. Use any 50 ΩSMA
cable to connect signals to the other connectors on the front panel of your NI 5761. For more information
about connecting I/O signals on your device, refer to the Specifications section of this document.

©National Instruments Corporation 7 NI 5761R User Guide and Specifications
Clocking
The NI 5761 clocks control the sample rate and other timing functions on the device. Table 3 contains
information about the possible NI 5761 clock resources.
Using Your NI 5761R with a LabVIEW FPGA Example VI
The NI FlexRIO Adapter Module Support software includes a variety of example projects to help get
you started creating your LabVIEW FPGA program. This section explains how to use an existing
LabVIEW FPGA example project to generate and acquire samples with the NI 5761R. This example
requires at least one SMA cable for connecting signals to your NI 5761R.
Note Examples available for your device are dependent on the device-specific minimum software
requirements. For more information about software requirements for your device, visit ni.com/
info and enter rdsoftwareversion as the Info Code to determine which minimum software
versions you need for your device.
Each NI 5761R example project includes the following components:
• A LabVIEW FPGA VI that can be compiled and run embedded in FPGA hardware
• A VI that runs in LabVIEW for Windows and interacts with the LabVIEW FPGA VI
Note In NI application software, NI FlexRIO adapter modules are referred to as IO Modules.
Complete the following steps to run an example that acquires a waveform on CH 0 of the NI 5761.
1. Connect one end of an SMA cable to CH 0 on the front panel of the NI 5761 and the other end of
the cable to your device under test (DUT).
2. Launch LabVIEW.
3. In the Getting Started window, click Find Examples to display the NI Example Finder.
4. In the NI Example Finder window, select Hardware Input and Output»FlexRIO»IO Modules»
NI 5761.
5. Select NI 5761 - Getting Started.lvproj.
6. In the Project Explorer window, open NI 5761 - Getting Started (Host).vi under My Computer.
The host VI opens. This VI uses the NI 7952R as the FPGA target by default. If you are using an
NI FlexRIO FPGA module other than the NI 7952R, complete the following steps to change to an
FPGA VI that supports your target.
a. Select Window»Show Block Diagram to open the VI block diagram.
b. On the block diagram, right-click the Open FPGA VI Reference (PXI-7952R) function and
select Configure Open FPGA VI Reference.
Table 3. NI 5761 Clock Sources
Clock Frequency Source Options
Sample Clock 175 MHz to 250 MHz • Internal VCO locked to a Reference clock
• External through the CLK IN connector
• External through IoModSyncClock
Reference Clock 10 MHz • Internal
• External through the CLK IN connector
• External through IoModSyncClock

NI 5761R User Guide and Specifications 8 ni.com
c. In the Configure Open FPGA VI Reference dialog box, click the Browse Project button in
the Open VI section.
d. In the Select VI dialog box that opens, expand the tree view for your device, select the VI
under your device and click OK.
e. Click OK in the Configure Open FPGA VI Reference dialog box.
f. Save the VI.
7. On the front panel, in the RIO Resource box, select an NI 5761R resource that corresponds with
the target configured in step 6.
8. Select AI 0 in the AI Channel box.
9. Set the Trigger Level (V) and the Record Size controls to the desired value.
10. In the Trigger Type box, you can select either Software Trigger or Data Edge. If you select
Software Trigger, the VI acquires data every time you click the Software Trigger button on the
front panel of the VI. If you select Data Edge, the VI acquires data every time an edge occurs.
11. Click the Run button to run the VI.
12. Click the Software Trigger button if you selected Software Trigger in the Trigger Type box. The
VI acquires data and displays the captured waveform on the Acquired Waveform graph as shown
in Figure 4.
13. Click STOP to stop the VI.
14. Close the VI.
Figure 4. NI 5761 - Getting Started (Host) VI Front Panel

©National Instruments Corporation 9 NI 5761R User Guide and Specifications
Creating a LabVIEW Project and Run a VI on an FPGA Target
This section explains how to setup your target and create an FPGA VI and host VI for data
communication. For more detailed information about acquiring data on your NI 5761R, refer to the
example VIs available on your NI FlexRIO Adapter Module Support software.
Creating a Project
1. Launch LabVIEW, or if LabVIEW is already running, select File»New.
2. In the New dialog box, select Project»Empty Project. Click OK. The new project opens in the
Project Explorer window.
3. Save the project as 5761SampleAcq.lvproj.
Creating an FPGA Target VI
1. In the Project Explorer window, right-click My Computer and select New»Targets and
Devices.
2. In the Add Targets and Devices on My Computer dialog box, select the Existing Target or
Device option button and expand the FPGA Target. The target is displayed.
3. Select your device and click OK. The target and target properties are loaded into the project tree.
4. In the Project Explorer window, expand FPGA Target (RIOx, PXI-79xxR).
5. Right-click the FPGA target and select New»FPGA Base Clock.
6. In the Resource pull-down menu, select IO Module Clock 0.
7. Enter 125 MHz in the Compile for single frequency control. Click OK.
8. Right-click the FPGA target and select New»FPGA Base Clock again.
9. In the Resource pull-down menu, select 200 MHz Clock. Click OK.
10. Right-click IO Module and select Properties. In the General category, you can see the available
CLIP for the NI 5761 in the Component Level IP pane. If the category information is dimmed,
select the Enable IO Module checkbox.
11. Select NI 5761 Multi Sample CLIP.
12. In the Clock Selections category, select 200 MHz Clock from the pull-down menu for Clk200.
Leave Clk40 configured as the Top -Level Clock. This step is necessary to compile the FPGA
Target VI correctly. Click OK.
Note Configuring these clocks is required for proper CLIP operation. Refer to the NI 5761 CLIP
topics in the NI FlexRIO Help for more information about configuring your clocks.
13. In the Project Explorer window, right-click the FPGA target and select New»VI. A blank VI
opens.
14. Select Window»Show Block Diagram to open the VI block diagram.
15. In the Project Explorer window, expand the IO Module (NI 5761 : NI 5761) tree view.
16. Select AI 0 Data N and AI 0 Data N-1 and drag them onto the block diagram.
17. Add a Timed Loop around the two nodes.
18. Wire an indicator to the output terminals of the IO Module\AI 0 Data N and IO Module\AI 0
Data N-1 nodes.
19. Wire an FPGA Clock Constant to the input node of the Timed Loop. Set this constant to
IO Module Clock 0.

NI 5761R User Guide and Specifications 10 ni.com
Your block diagram should now resemble the block diagram in Figure 5.
Figure 5. 5761SampleAcq (FPGA).vi Block Diagram
Tip Click the Clean Up Diagram button on the toolbar to cleanly organize the VI block diagrams.
20. Save the VI as 5761SampleAcq (FPGA).vi.
21. Close the VI.
22. In the Project Explorer window under My Computer, expand the tree view for your device,
right-click 5761SampleAcq (FPGA).vi and select Compile to compile the files for your target.
The Generating Intermediate Files window opens and displays the compilation progress.
The LabVIEW FPGA Compile Server window opens and runs. The compilation takes several
minutes.
23. When the compilation completes, click the Stop Server button.
24. Click Close in the Successful Compile Report window.
25. Save and close the VI.
26. Save the project.
Creating a Host VI
1. In the Project Explorer window, right-click My Computer and select New»VI. A blank VI opens.
Select Window»Show Block Diagram to open the VI block diagram.
2. Add the Open FPGA VI Reference function, located on the FPGA Interface palette, to the block
diagram.
3. Right-click the Open FPGA VI Reference function, labeled No Target, and select Configure
Open FPGA VI Reference.
4. In the Configure Open FPGA VI Reference dialog box, select the VI option button.
5. In the Select VI window that opens, select 5761SampleAcq (FPGA).vi under your device, and
click OK.
6. Click OK in the Configure Open FPGA VI Reference dialog box. The new target name appears
under the Open FPGA VI Reference function in the block diagram.
7. Add a While Loop to the block diagram.
8. Right-click the stop condition inside the While Loop and select Create Control to create a
STOP control on the VI front panel.
9. Add the Read/Write Control function, located on the FPGA Interface palette, inside the
While Loop.
10. Wire the FPGA VI Reference Out indicator of the Open FPGA VI Reference function to the
FPGA VI Reference In control on the Read/Write Control function.

©National Instruments Corporation 11 NI 5761R User Guide and Specifications
11. Wire the error out indicator of the Open FPGA VI Reference function to the error in control of
the Read/Write Control function.
12. Configure the Read/Write Control function by clicking the terminal section labeled Unselected,
and selecting IO Module/AI 0 Data N.
13. Add the IO Module/AI 0 Data N-1 I/O item to the Read/Write Control function by clicking the
lower edge of the control node with the Positioning tool and dragging the edge down.
14. Wire an indicator to the output terminal of the IO Module\AI 0 Data N node.
15. Wire an Indicator from the output terminal of the IO Module\AI 0 Data N-1 node.
16. Add the Close FPGA VI Reference function, located on the FPGA Interface palette, to the right
of the While Loop on the block diagram.
17. Wire the FPGA VI Reference Out indicator of the Read/Write Control function to the FPGA VI
Reference In control of the Close FPGA VI Reference function.
18. Wire the error out indicator of the Read/Write Control function to the error in control of the
Close FPGA VI Reference function.
Your block diagram should now resemble the block diagram in Figure 6.
Figure 6. 5761SampleAcq(Host).vi Block Diagram
19. Save the VI as 5761SampleAcq(Host).vi.
Running the Host VI
1. Connect one end of an SMA cable to CH 0 on the front panel of the NI 5761 and the other end of
the cable to your DUT.
2. Open the front panel of 5761SampleAcq(Host).vi.
3. Click the Run button to run the VI.
4. The VI acquires data from the DUT on AI 0 Data N and AI 0 Data N-1.
5. Click the STOP button on the front panel and close the VI.

NI 5761R User Guide and Specifications 12 ni.com
How to Use Your NI FlexRIO Documentation Set
Refer to the Figure 7 and Table 4 for information about how to use your NI FlexRIO documentation set.
Figure 7. How to Use Your NI FlexRIO Documentation Set
Table 4. NI FlexRIO Documentation Locations and Descriptions
Document Location Description
NI FlexRIO FPGA
Module Installation
Guide and Specifications*
Available in your FPGA module
hardware kit and from the Start Menu.
Contains installation instructions for your
NI FlexRIO system and specifications for your
FPGA module.
NI Adapter Module User
Guide and Specifications*
Available in your adapter module
hardware kit and from the Start Menu.
Contains signal information, examples, and
specifications for your adapter module.
LabVIEW FPGA Module
Help*
Embedded in LabVIEW Help.Contains information about the basic functionality of
LabVIEW FPGA Module.
NI FlexRIO Help*Embedded in LabVIEW FPGA
Module Help.
Contains FPGA module, adapter module, and CLIP
configuration information.
LabVIEW Examples Available in LabVIEW Example
Finder.
Contains examples of how to run FPGA VIs and
Host VIs on your device.
Other Useful Information on ni.com
ni.com/ipnet Contains LabVIEW FPGA functions and intellectual property to share.
ni.com/flexrio Contains product information and data sheets for NI FlexRIO devices.
* These documents are also available at ni.com/manuals.
LabVIEW FPGA
Module Help
NI FlexRIO
Help
LabVIEW
Examples
INSTALL Hardware
and Software
CONNECT Signals
and Learn About
Your Adapter
Module
LEARN About
LabVIEW FPGA
Module
PROGRAM Your
NI FlexRIO System
in LabVIEW FPGA
Module
NI FlexRIO FPGA Module
Installation Guide and Specifications
NI FlexRIO Adapter Module
User Guide and Specifications
Are
You New to
LabVIEW FPGA
Module?
Yes No
No

©National Instruments Corporation 13 NI 5761R User Guide and Specifications
Specifications
This section lists the specifications of the NI FlexRIO adapter module (NI 5761). Pair these
specifications with the specifications listed in the NI FlexRIO FPGA Module Installation Guide and
Specifications. For more information about safety and electromagnetic compatibility refer to the Read
Me First: Safety and Electromagnetic Compatibility document included in your hardware kit or
available at ni.com/manuals.
Caution To avoid permanent damage to the NI 5761, disconnect all signals connected to the NI 5761
before powering down the module, and only connect signals after the module has been powered on
by the NI FlexRIO FPGA module.
Note All numeric specifications are typical unless otherwise noted. All graphs illustrate the
performance of a representative module.
Typical values describe useful product performance that are not covered by warranty. Typical values
cover the expected performance of units over ambient temperature ranges of 23 ±5 °C with a 90%
confidence level, based on measurements taken during development or production.
Analog Input (AI CH 0 through AI CH 3)
General Characteristics
Number of channels ...............................................Four, single-ended, simultaneously sampled
Connector...............................................................SMA
Input impedance.....................................................50 Ω, per connector
Sample rate
Internal Sample clock ....................................250 MHz
External Sample clock ...................................175 MHz to 250 MHz
Digital data range...................................................±8,191
ADC part number...................................................ADS62P491; 14-bit resolution, dual ADC
AC-Coupled Specifications
Input range (normal operating conditions) ............2.07 Vpk-pk
Absolute maximum input.......................................±10 V DC, 5 Vpk-pk AC
Bandwidth (–3 dB).................................................0.1 MHz to 500 MHz
Bandwidth (–1 dB).................................................1 MHz to 250 MHz
1 For additional information on the ADS62P49, refer to the Texas Instruments device data sheet at www.ti.com.

NI 5761R User Guide and Specifications 14 ni.com
Table 5 lists the AC-coupled spectral performance measurements. All values are measured with a
250 MHz external Sample clock.
Channel to channel isolation
1 MHz ............................................................>90 dB
100.1 MHz .....................................................90 dB
501 MHz ........................................................80 dB
AC-Coupled Measurements
Figure 8. AC-Coupled Bandwidth (Passband)
Table 5. AC-Coupled Spectral Performance
Measurement 20.17 MHz 70.17 MHz*123.17 MHz*
SNR 72.5 dB 71.4 dB 70.5 dB
SINAD 72.3 dB 71.2 dB 70.3 dB
SFDR 88 dB 84 dB 80 dB
* These measurements were extrapolated from a –4 dBFS plot.
1M80k
–15
–14
–13
–12
–11
–10
–9
–8
–7
–6
–5
–4
–3
–2
–1
0
1
2
3
4
5
Gain (dB)
Frequency (Hz)
100k 10M 100M 700M

©National Instruments Corporation 15 NI 5761R User Guide and Specifications
Figure 9. AC-Coupled Spectral Measurements: 19.5 MHz and 20.5 MHz,
–13 dBFS, 8,192 Point FFT, 10 RMS Average
Figure 10. AC-Coupled Spectral Measurements: 20.1 MHz, –1 dBFS, 8,192 Point FFT, 10 RMS Average
200
–115
–110
–105
–100
–95
–90
–85
–80
–75
–70
–65
–60
–55
–50
–45
–40
–35
–30
–25
–20
–15
–10
–5
0
Amplitude (dBFS)
Frequency (MHz)
40 60 80 100 120
100
–115
–110
–105
–100
–95
–90
–85
–80
–75
–70
–65
–60
–55
–50
–45
–40
–35
–30
–25
–20
0
Amplitude (dBFS)
Frequency (MHz)
–15
–10
–5
20 30 40 50 60 70 90 100 110 12080

NI 5761R User Guide and Specifications 16 ni.com
Figure 11. AC-Coupled Spectral Measurements: Terminated, 8,192 Point FFT, 10 RMS Average
DC-Coupled Specifications
Input range (normal operating conditions) ............1.23 Vpk-pk
Absolute maximum input.......................................±4.5 V DC
Bandwidth (–3 dB).................................................DC to 500 MHz
Bandwidth (–1 dB).................................................DC to 250 MHz
Table 6 lists the DC-coupled spectral performance measurements. All values are measured with a
250 MHz external Sample clock.
Channel to channel isolation
1 MHz ............................................................>90 dB
100.1 MHz .....................................................80 dB
501 MHz ........................................................70 dB
Table 6. DC-Coupled Spectral Performance
Measurement 20.1 MHz 70.1 MHz 122.1 MHz
SNR 65.7 dB 64.3 dB 63 dB
SINAD 65.2 dB 61.8 dB 56.6 dB
SFDR 76 dB 65 dB 58 dB
0
–115
–110
–105
–100
–95
–90
–85
–80
–75
–70
–65
–60
–55
–50
–45
–40
–35
–30
–25
–20
0
Amplitude (dBFS)
Frequency (MHz)
–15
–10
–5
20 40 60 100 12080

©National Instruments Corporation 17 NI 5761R User Guide and Specifications
Note To ensure proper device operation, DC-coupled channels on the NI 5761 must see 50 Ωat DC
looking back at their source. If you are connecting a to source with an output impedance less than
50 Ω, you can add series resistance close to the source to properly bias the NI 5761 input terminals.
You can also use the NI 5761 input channel bias DACs to remove DC offset present in the system.
For more information about programming the bias DACs, refer to the NI 5761 CLIP topics in the
NI FlexRIO Help.
DC-Coupled Measurements
Figure 12. DC-Coupled Bandwidth (Passband)
100
–15
–14
–13
–12
–11
–10
–9
–8
–7
–6
–5
–4
–3
–2
–1
0
1
2
3
4
5
Gain (dB)
Frequency (Hz)
100 1k 10k 100k 1M 10M 100M 700M

NI 5761R User Guide and Specifications 18 ni.com
Figure 13. DC-Coupled Spectral Measurements: 19.5 MHz and 20.5 MHz,
–13 dBFS, 8,192 Point FFT, 10 RMS Average
Figure 14. DC-Coupled Spectral Measurements: 20.1 MHz, –1 dBFS, 8,192 Point FFT, 10 RMS Average
0
–115
–110
–105
–100
–95
–90
–85
–80
–75
–70
–65
–60
–55
–50
–45
–40
–35
–30
–25
–20
0
Amplitude (dBFS)
Frequency (MHz)
–15
–10
–5
25 50 75 100 125
0
–115
–110
–105
–100
–95
–90
–85
–80
–75
–70
–65
–60
–55
–50
–45
–40
–35
–30
–25
–20
0
Amplitude (dBFS)
Frequency (MHz)
–15
–10
–5
10 20 30 40 50 60 70 80 90 100 110 120