usrp

Control NI USRP radio device

Since R2024a

Add-On Required: This feature requires the Wireless Testbench™ Support Package for NI™ USRP™ Radios add-on.

Description

The usrp System object™ streams samples from the radio front end of an NI™ USRP™ radio device with a custom FPGA image that you create by using the Target NI USRP Radios Workflow.

To stream samples from the radio front end:

1. Create the usrp object and set its properties.

2. Call the object with arguments, as if it were a function.

To learn more about how System objects work, see What Are System Objects?

The diagram shows an overview of the internal architecture of an NI USRP radio. The usrp System object enables you to:

• Configure the radio front end by setting the object properties.

• Stream samples from the radio front end by calling the object with device() as if the object were a function.

• Transmit a test waveform over the air by using the transmit function. With this function, you can test the receive path on your DUT.

• Retrieve captured data from the PL DDR buffer by using the capture function. With this function, you can test the transmit path on your DUT.

For details on how to use the usrp System object with object functions to connect to, configure, and control your NI USRP radio device, see the call sequence in Object Functions.

For more information about time synchronization with a usrp System object, see Time Synchronize Operations on NI USRP Radios.

Creation

Syntax

device = usrp(radio)

device = usrp(radio,PropertyName=Value)

Description

device = usrp(radio) creates a usrp System object for the specified radio radio.

device = usrp(radio,PropertyName=Value) sets properties using one or more name-value arguments. For example, TransmitCenterFrequency=2.4e9 specifies a center frequency of 2.4 GHz on all DUT output and transmit antennas.

Input Arguments

radio — Radio setup configuration

string scalar | radio object

Radio setup configuration, specified as one of these options.

• String scalar — The name of a radio setup configuration you saved using the Radio Setup wizard. To list all saved radio setup configurations, call the radioConfigurations function with no input arguments. For example, "MyRadio".

• Radio object — A radio object that corresponds to a radio setup configuration you saved using the Radio Setup wizard. For example, to create a radio object for a radio setup configuration with the name "MyRadio", call radio = radioConfigurations("MyRadio").

  Use this option when you want to use synchronization features. You can refer to radio object properties to get information about the radio setup configuration that the object corresponds to, such as the model number of the radio, the radio IP address, and the synchronization options. Additionally, you can:

  • Check the lock status of the reference clock, local oscillators, or GPS disciplined oscillator (GPSDO) on the radio using the referenceLockedStatus, loLockedStatus, and gpsLockedStatus functions respectively.

  • Get the current radio time using the getRadioTime function.

  • Synchronize multiple devices by setting the radio time using the getTimeLastPPS and setTimeNextPPS functions.

  • Get time and GPS information from the radio using the getGPSTime and getGPSNMEA functions.

  • Schedule synchronized property updates on your usrp object using the setCommandTime, getCommandTime, and clearCommandTime functions.

  For more information, see Time Synchronize Operations on NI USRP Radios.

You can use these synchronization features to time synchronize a streaming operation to or from the radio by specifying the StartTime name value argument when you call the transmit function or when you stream samples from the radio by calling the usrp System object as a function. Additionally, you can use synchronization features to synchronize operations multiple radios. For more information, see Time Synchronize Operations on NI USRP Radios.

For a list of supported radios, see Supported Radio Devices.

Properties

Unless otherwise indicated, properties are nontunable, which means you cannot change their values after calling the object. Objects lock when you call them, and the release function unlocks them.

If a property is tunable, you can change its value at any time.

For more information on changing property values, see System Design in MATLAB Using System Objects.

Radio Antenna Properties

TransmitCenterFrequency — Center frequency in Hz of DUT output and transmit antennas

2.4e9 (default) | positive numeric scalar | numeric array

Radio center frequency in Hz, specified as one of these options:

• Positive numeric scalar — The object applies this value by scalar expansion to each antenna specified in the DUTOutputAntennas and TransmitAntennas properties.

• Numeric array — The object applies the ith array element value to the ith antenna in the DUTOutputAntennas and TransmitAntennas properties, in that order.

The valid center frequency range depends on the radio device.

Radio Device	Center Frequency
USRP E320 (since R2025a)	70 MHz to 6 GHz
USRP N310	1 MHz to 6 GHz
USRP N320	1 MHz to 6 GHz
USRP N321	1 MHz to 6 GHz
USRP X310	10 MHz to 6 GHz
USRP X410	1 MHz to 8 GHz

Note

When setting this property for multiple antennas on a USRP N310 radio, consider these hardware characteristics:

• The antenna ports on the RF0 and RF1 radio channels use the same center frequency. Therefore, set identical center frequency values for the antennas specified as "RF0:TX/RX" and "RF1:TX/RX".

• The antenna ports on the RF2 and RF3 radio channels use the same center frequency. Therefore, set identical center frequency values for the antennas specified as "RF2:TX/RX" and "RF3:TX/RX".

Tunable: Yes

Data Types: double

TransmitRadioGain — Gain in dB of DUT output and transmit antennas

10 (default) | positive numeric scalar | numeric array

Gain in dB of the DUT output and transmit antennas, specified as one of these options:

• Positive numeric scalar — The object applies this value by scalar expansion to each antenna that you specify in the DUTOutputAntennas and TransmitAntennas properties.

• Numeric array — The object applies the ith array element value to the ith antenna in the DUTOutputAntennas and TransmitAntennas properties, in that order.

The valid gain range depends on the radio device.

Radio Device	Transmit Radio Gain
USRP E320 (since R2025a)	0 dB to 89.8 dB
USRP N310	0 dB to 65 dB
USRP N320	0 dB to 60 dB
USRP N321	0 dB to 60 dB
USRP X310	0 dB to 31.5 dB
USRP X410	0 dB to 60 dB

Tunable: Yes

Data Types: double

ReceiveCenterFrequency — Center frequency in Hz of DUT input and capture antennas

2.4e9 (default) | positive numeric scalar | numeric array

Radio center frequency in Hz, specified as one of these options:

• Positive numeric scalar — The object applies this value by scalar expansion to each antenna specified in the DUTInputAntennas and CaptureAntennas properties.

• Numeric array — The object applies the ith array element value to the ith antenna in the DUTInputAntennas and CaptureAntennas properties, in that order.

The valid center frequency range depends on the radio device.

Radio Device	Center Frequency
USRP E320 (since R2025a)	70 MHz to 6 GHz
USRP N310	1 MHz to 6 GHz
USRP N320	1 MHz to 6 GHz
USRP N321	1 MHz to 6 GHz
USRP X310	10 MHz to 6 GHz
USRP X410	1 MHz to 8 GHz

Note

When setting this property for multiple antennas on a USRP N310 radio, consider these hardware characteristics:

• The antenna ports on the RF0 and RF1 radio channels use the same center frequency. Therefore, set identical center frequency values for the antennas specified as "RF0:RX2" and "RF1:RX2".

• The antenna ports on the RF2 and RF3 radio channels use the same center frequency. Therefore, set identical center frequency values for the antennas specified as "RF2:RX2" and "RF3:RX2".

Tunable: Yes

Data Types: double

ReceiveRadioGain — Gain in dB of DUT input and capture antennas

10 (default) | positive numeric scalar | numeric array

Gain in dB of the DUT input and capture antennas, specified as one of these options:

• Positive numeric scalar — The object applies this value by scalar expansion to each antenna that you specify in the DUTInputAntennas and CaptureAntennas properties.

• Numeric array — The object applies the ith array element value to the ith antenna in the DUTInputAntennas and CaptureAntennas properties, in that order.

The valid gain range depends on the radio device.

Radio Device	Capture Radio Gain
USRP E320 (since R2025a)	0 dB to 76 dB
USRP N310	0 dB to 75 dB
USRP N320	0 dB to 60 dB
USRP N321	0 dB to 60 dB
USRP X310	0 dB to 31.5 dB
USRP X410	0 dB to 60 dB

Tunable: Yes

Data Types: double

SampleRate — Baseband sample rate of the radio front end in Hz

positive numeric scalar

Baseband sample rate of the radio front end in Hz, specified as a positive numeric scalar. The default is the sample rate that you specify in the Configure HDL Code Generation Settings step of the targeting workflow.

Set a sample rate of MCR, or MCR divided by a supported decimation or interpolation factor, where MCR is a valid master clock rate. The valid MCR and decimation or interpolation factor values depend on the radio.

Radio Device	MCR
USRP E320 (since R2025a)	Using one transmit channel, one receive channel, or both: 40.00 MHz 50.00 MHz 61.44 MHz Using two transmit or receive channels: 20.00 MHz 25.00 MHz 30.72 MHz
USRP N310	122.88 MHz 125.00 MHz 153.60 MHz
USRP N320	200.00 MHz 245.76 MHz 250.00 MHz
USRP N321	200.00 MHz 245.76 MHz 250.00 MHz
USRP X310	184.32 MHz 200.00 MHz
USRP X410	245.76 MHz 250.00 MHz

Radio	Supported Decimation or Interpolation Factor
USRP E320 (since R2025a) USRP N310 USRP N320 USRP N321 USRP X410	1
	2
	3
	Even integer in the range from 4 to 256
	Multiple of 4 in the range from 256 to 512
	Multiple of 8 in the range from 512 to 1016
USRP X310	Integer in the range from 1 to 128
	Even integer in the range from 128 to 256
	Multiple of 4 in the range from 256 to 512
	Multiple of 8 in the range from 512 to 1016

Data Types: double

DUTInputAntennas — Radio antennas for input to the DUT

string scalar | string array

Radio antennas for input to the DUT, specified as one of these options:

• String scalar — Specify the use of a single antenna.

• String array — Specify the use of multiple antennas.

If you specify multiple antennas, the object assigns them to the input data streaming interfaces in the DUT in order. For example, the object assigns the first antenna to input data streaming interface 0, and the Nth antenna to input data streaming interface N-1. You map the input data streaming interfaces to the hardware interfaces in the Map Data Streaming Inputs step of the targeting workflow.

Use this table to identify the supported radio antenna ports on the radio device and the corresponding string constants that you can specify for this property. The default value depends on the radio.

Radio Device	Supported Antenna Port	String Scalar
USRP E320 (since R2025a)	RFA channel: RX2 port	"RFA:RX2" (default)
	RFB channel: RX2 port	"RFB:RX2"
USRP N310	RF0 channel: RX2 port	"RF0:RX2" (default)
	RF1 channel: RX2 port	"RF1:RX2"
	RF2 channel: RX2 port	"RF2:RX2"
	RF3 channel: RX2 port	"RF3:RX2"
USRP N320	RF0 channel: RX2 port	"RF0:RX2" (default)
	RF1 channel: RX2 port	"RF1:RX2"
USRP N321	RF0 channel: RX2 port	"RF0:RX2" (default)
	RF0 channel: RX2 port	"RF1:RX2"
USRP X310	RFA channel: RX2 port	"RFA:RX2" (default)
	RFB channel: RX2 port	"RFB:RX2"
USRP X410	DB0 RF0 channel: RX 1 port	"DB0:RF0:RX1" (default)
	DB0 RF1 channel: RX 1 port	"DB0:RF1:RX1"
	DB1 RF0 channel: RX 1 port	"DB1:RF0:RX1"
	DB1 RF1 channel: RX 1 port	"DB1:RF1:RX1"

The maximum number of antenna connections available depends on the radio. Use this table to determine the maximum combined number of antennas you can specify with the DUTInputAntennas, DUTOutputAntennas, CaptureAntennas, and TransmitAntennas properties.

Radio Device	Maximum Number of Antennas
USRP E320 (since R2025a)	2
USRP N310	4
USRP N320	4
USRP N321	4
USRP X310	2
USRP X410	4

Example: DUTInputAntennas=["RF0:RX2","RF1:RX2"] specifies two DUT input antennas.

Data Types: string

DUTOutputAntennas — Radio antennas for transmit from DUT

string scalar | string array

Radio antennas for transmitting from DUT, specified as one of these options:

• String scalar — Specify the use of a single antenna.

• String array — Specify the use of multiple antennas.

If you specify multiple antennas, the object assigns them to the output data streaming interfaces in the DUT in order. For example, the object assigns the first antenna to output data streaming interface 0, and the Nth antenna to output data streaming interface N-1. You map the output data streaming interfaces to the hardware interfaces in the Map Data Streaming Outputs step of the targeting workflow.

Use this table to identify the supported radio antenna ports on the radio device and the corresponding string constants that you can specify for this property. The default value depends on the radio.

Radio Device	Supported Antenna Port	String Scalar
USRP E320 (since R2025a)	RFA channel: TX/RX port	"RFA:TX/RX" (default)
	RFB channel: TX/RX port	"RFB:TX/RX"
USRP N310	RF0 channel: TX/RX port	"RF0:TX/RX" (default)
	RF1 channel: TX/RX port	"RF1:TX/RX"
	RF2 channel: TX/RX port	"RF2:TX/RX"
	RF3 channel: TX/RX port	"RF3:TX/RX"
USRP N320	RF0 channel: TX/RX port	"RF0:TX/RX" (default)
	RF1 channel: TX/RX port	"RF1:TX/RX"
USRP N321	RF0 channel: TX/RX port	"RF0:TX/RX" (default)
	RF1 channel: TX/RX port	"RF1:TX/RX"
USRP X310	RFA channel: TX/RX port	"RFA:TX/RX" (default)
	RFB channel: TX/RX port	"RFB:TX/RX"
USRP X410	DB0 RF0 channel: TX/RX 0 port	"DB0:RF0:TX/RX0" (default)
	DB0 RF1 channel: TX/RX 0 port	"DB0:RF1:TX/RX0"
	DB1 RF0 channel: TX/RX 0 port	"DB1:RF0:TX/RX0"
	DB1 RF1 channel: TX/RX 0 port	"DB1:RF1:TX/RX0"

The maximum number of antenna connections available depends on the radio. Use this table to determine the maximum combined number of antennas you can specify with the DUTInputAntennas, DUTOutputAntennas, CaptureAntennas, and TransmitAntennas properties.

Radio Device	Maximum Number of Antennas
USRP E320 (since R2025a)	2
USRP N310	4
USRP N320	4
USRP N321	4
USRP X310	2
USRP X410	4

Example: DUTOutputAntennas=["RF0:TX/RX","RF1:TX/RX"] specifies two DUT output antennas.

Data Types: string

CaptureAntennas — Radio antennas for capture to host

"No Antennas Selected" (default) | string scalar | string array

Radio antennas for capture to the host, specified as one of these options:

• "No Antennas Selected" — Specify no antennas.

• String scalar — Specify the use of a single antenna.

• String array — Specify the use of multiple antennas.

Use this table to identify the supported radio antenna ports on the radio device and the corresponding string constants that you can specify for this property. The default value depends on the radio.

Radio Device	Supported Antenna Port	String Scalar
USRP E320 (since R2025a)	RFA channel: RX2 port	"RFA:RX2" (default)
	RFB channel: RX2 port	"RFB:RX2"
USRP N310	RF0 channel: RX2 port	"RF0:RX2" (default)
	RF1 channel: RX2 port	"RF1:RX2"
	RF2 channel: RX2 port	"RF2:RX2"
	RF3 channel: RX2 port	"RF3:RX2"
USRP N320	RF0 channel: RX2 port	"RF0:RX2" (default)
	RF1 channel: RX2 port	"RF1:RX2"
USRP N321	RF0 channel: RX2 port	"RF0:RX2" (default)
	RF0 channel: RX2 port	"RF1:RX2"
USRP X310	RFA channel: RX2 port	"RFA:RX2" (default)
	RFB channel: RX2 port	"RFB:RX2"
USRP X410	DB0 RF0 channel: RX 1 port	"DB0:RF0:RX1" (default)
	DB0 RF1 channel: RX 1 port	"DB0:RF1:RX1"
	DB1 RF0 channel: RX 1 port	"DB1:RF0:RX1"
	DB1 RF1 channel: RX 1 port	"DB1:RF1:RX1"

The maximum number of antenna connections available depends on the radio. Use this table to determine the maximum combined number of antennas you can specify with the DUTInputAntennas, DUTOutputAntennas, CaptureAntennas, and TransmitAntennas properties.

Radio Device	Maximum Number of Antennas
USRP E320 (since R2025a)	2
USRP N310	4
USRP N320	4
USRP N321	4
USRP X310	2
USRP X410	4

Example: CaptureAntennas=["RF2:RX2","RF3:RX2"] specifies two capture antennas.

Data Types: string

TransmitAntennas — Radio antennas for transmit from host

"No Antennas Selected" (default) | string scalar | string array

Radio antennas for transmitting from the host, specified as one of these options:

• "No Antennas Selected" — Specify no antennas.

• String scalar — Specify the use of a single antenna.

• String array — Specify the use of multiple antennas.

Use this table to identify the supported radio antenna ports on the radio device and the corresponding string constants that you can specify for this property. The default value depends on the radio.

Radio Device	Supported Antenna Port	String Scalar
USRP E320 (since R2025a)	RFA channel: TX/RX port	"RFA:TX/RX" (default)
	RFB channel: TX/RX port	"RFB:TX/RX"
USRP N310	RF0 channel: TX/RX port	"RF0:TX/RX" (default)
	RF1 channel: TX/RX port	"RF1:TX/RX"
	RF2 channel: TX/RX port	"RF2:TX/RX"
	RF3 channel: TX/RX port	"RF3:TX/RX"
USRP N320	RF0 channel: TX/RX port	"RF0:TX/RX" (default)
	RF1 channel: TX/RX port	"RF1:TX/RX"
USRP N321	RF0 channel: TX/RX port	"RF0:TX/RX" (default)
	RF1 channel: TX/RX port	"RF1:TX/RX"
USRP X310	RFA channel: TX/RX port	"RFA:TX/RX" (default)
	RFB channel: TX/RX port	"RFB:TX/RX"
USRP X410	DB0 RF0 channel: TX/RX 0 port	"DB0:RF0:TX/RX0" (default)
	DB0 RF1 channel: TX/RX 0 port	"DB0:RF1:TX/RX0"
	DB1 RF0 channel: TX/RX 0 port	"DB1:RF0:TX/RX0"
	DB1 RF1 channel: TX/RX 0 port	"DB1:RF1:TX/RX0"

The maximum number of antenna connections available depends on the radio. Use this table to determine the maximum combined number of antennas you can specify with the DUTInputAntennas, DUTOutputAntennas, CaptureAntennas, and TransmitAntennas properties.

Radio Device	Maximum Number of Antennas
USRP E320 (since R2025a)	2
USRP N310	4
USRP N320	4
USRP N321	4
USRP X310	2
USRP X410	4

Example: TransmitAntennas=["RF2:TX/RX","RF3:TX/RX"] specifies two transmit antennas.

Data Types: string

CaptureDDRAllocation — Allocated PL DDR buffer memory in samples for capture antennas

10e6 (default) | even positive integer

Allocated PL DDR buffer memory in samples for the capture antennas, specified as an even positive integer. This is the memory allocated to each specified capture antenna specified in CaptureAntennas.

The value assigned to this property is the largest number of IQ samples you can request with the capture function.

The total memory allocation must not exceed the memory buffer size on the radio. Several streaming connections through the PL DDR buffer contribute to the total memory allocation.

• For each antenna that you specify in CaptureAntennas, CaptureDDRAllocation samples are allocated.

• For each antenna that you specify in TransmitAntennas, TransmitDDRAllocation samples are allocated.

• For each data streaming connection between the DUT and the PL DDR buffer, the memory allocation is determined by the DDRAllocation you specify when you add streaming interfaces to your DUT with the addRFNoCStreamInterface function.

The memory buffer size depends on the radio.

Radio Device	Memory Buffer Size	Maximum Data Samples
USRP E320 (since R2025a)	2 GB	229
USRP N310	2 GB	229
USRP N320	2 GB	229
USRP N321	2 GB	229
USRP X310	1 GB	228
USRP X410	4 GB	230

Data Types: double

TransmitDDRAllocation — Allocated PL DDR buffer memory in samples for transmit antennas

10e6 (default) | even positive integer

Allocated PL DDR buffer memory in samples for the transmit antennas, specified as an even positive integer. This is the memory allocated to each specified capture antenna specified in TransmitAntennas.

The value assigned to this property is the largest number of IQ samples you can request with the transmit function.

The total memory allocation must not exceed the memory buffer size on the radio. Several streaming connections through the PL DDR buffer contribute to the total memory allocation.

• For each antenna that you specify in CaptureAntennas, CaptureDDRAllocation samples are allocated.

• For each antenna that you specify in TransmitAntennas, TransmitDDRAllocation samples are allocated.

• For each data streaming connection between the DUT and the PL DDR buffer, the memory allocation is determined by the DDRAllocation you specify when you add streaming interfaces to your DUT with the addRFNoCStreamInterface function.

The memory buffer size depends on the radio.

Radio Device	Memory Buffer Size	Maximum Data Samples
USRP E320 (since R2025a)	2 GB	229
USRP N310	2 GB	229
USRP N320	2 GB	229
USRP N321	2 GB	229
USRP X310	1 GB	228
USRP X410	4 GB	230

Data Types: double

Advanced Properties

DUTClockFrequency — Clock frequency of the DUT in Hz

Read-only: positive numeric scalar

Since R2024b

This property is read-only.

Clock frequency of the DUT in Hz, returned as a positive numeric scalar.

The clock frequency of the DUT depends on the Reference Design Settings set in the Generate HDL Code step of the targeting workflow.

• If the DUT Clock Source configuration parameter is set to Radio, the clock frequency of the DUT is the MCR of the radio that the specified SampleRate is derived from.

• If the DUT Clock Source configuration parameter is set to Custom, the clock frequency of the DUT is the value specified in the Target Frequency configuration parameter.

Example: 250000000

Data Types: double

LoopbackMode — Option to enable loopback of IQ samples from transmit to receive antennas

"Disabled" (default) | "FPGA"

Option to enable the loopback of IQ samples from the transmit to receive antennas, specified as "Disabled" or "FPGA".

Set the LoopbackMode property to "FPGA" to loop back samples from DUTOutputAntennas and TransmitAntennas to DUTInputAntennas and CaptureAntennas. This option enables you to test the transmit or receive path of the algorithm on your DUT as if it is connected to an antenna without sending or receiving data over the air. This table details which antennas loop back to each other when you specify this option.

Radio Device	Transmit Antenna	Receive Antenna
USRP E320 (since R2025a)	"RFA:TX/RX"	"RFA:RX2"
	"RFB:TX/RX"	"RFB:RX2"
USRP N310	"RF0:TX/RX"	"RF0:RX2"
	"RF1:TX/RX"	"RF1:RX2"
	"RF2:TX/RX"	"RF2:RX2"
	"RF3:TX/RX"	"RF3:RX2"
USRP N320 USRP N321	"RF0:TX/RX"	"RF0:RX2"
	"RF1:TX/RX"	"RF1:RX2"
USRP X310	"RFA:TX/RX"	"RFA:RX2"
	"RFB:TX/RX"	"RFB:RX2"
USRP X410	"DB0:RF0:TX/RX0"	"DB0:RF0:RX1"
	"DB0:RF1:TX/RX0"	"DB0:RF1:RX1"
	"DB1:RF0:TX/RX0"	"DB1:RF0:RX1"
	"DB1:RF1:TX/RX0"	"DB1:RF1:RX1"

Data Types: string

BypassDUT — Flag to remove DUT from signal path

0(false) (default) | 1(true)

Flag to remove the DUT from the signal path, specified as 0(false) or 1(true).

Set this flag to 1(true) to disconnect all DUT streaming interfaces that you assign in the Map Target Interfaces step of the targeting workflow. This frees up hardware resources to assign TransmitAntennas and CaptureAntennas for transmit and capture data directly to the host.

Data Types: logical

BypassPLDDRBuffer — Flag to remove PL DDR buffer from signal path

0(false) (default) | 1(true)

Flag to remove the PL DDR buffer from the signal path, specified as 0(false) or 1(true).

Set this flag to 1(true) to disconnect all DUT streaming interfaces source or sink connections that you set to PL DDR Buffer in the Map Target Interfaces step of the targeting workflow. This option connects the source or sink connection directly to the host instead.

Data Types: logical

Usage

Syntax

device()

device(numSamples)

device(___,Name=Value)

Description

device() streams samples continuously from the radio front end until you call the reset function.

device(numSamples) streams numSamples samples from the radio front end.

device(___,Name=Value) specifies options using one or more name-value arguments in addition to the input arguments in the previous syntaxes. For example, startTime=getRadioTime(radio)+0.5 schedules the streaming of samples to start 500 milliseconds in the future. (since R2025a)

Input Arguments

numSamples — Number of samples

integer number of samples

Number of samples, specified as an integer number of samples.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: getRadioTime(radio)+0.5 schedules the streaming of samples to start 500 milliseconds in the future.

StartTime — Start time for streaming samples from radio

getRadioTime(radio)+1 (default) | positive numeric scalar

Since R2025a

Start time for streaming samples from the radio, specified as a positive numeric scalar. The default value is one second in the future. To schedule the System object to start streaming samples from the radio at a specific future time, first use the getRadioTime function to get the current radio time in seconds. Then, specify the radio time at which you want to start streaming samples from the radio.

For more information about how to schedule transmit and receive operations, see Time Synchronize Operations on NI USRP Radios.

Example: getRadioTime(radio)+0.5 schedules the operation to start 500 milliseconds in the future.

Data Types: double

Background — Flag to specify blocking behavior

false (default) | true

Since R2025a

Flag to specify the blocking behaviour of the delay specified with the StartTime name-value argument, specified as one of these options:

• false — The delay specified with StartTime blocks MATLAB^®. You can run MATLAB code only when the current time reaches the scheduled start time.

• true — The delay specified with StartTimeelapses in the background. Use this option to run MATLAB code while waiting for the current time to reach the scheduled start time. When you specify this option, consider that new samples are not available in the buffer until the delay elapses and the streaming operation starts.

Data Types: logical

Object Functions

To use an object function, specify the System object as the first input argument. For example, to release system resources of a System object named obj, use this syntax:

release(obj)

Specific to usrp

programFPGA	Program FPGA on NI USRP radio device with custom bitstream
describeFPGA	Describe hardware interfaces on NI USRP radio device FPGA
capture	Retrieve captured IQ data from an NI USRP radio device
transmit	Transmit waveform over the air with an NI USRP radio device
stopTransmission	Stop transmission from an NI USRP radio device

Common to All System Objects

setup	One-time set up tasks for System objects
step	Run System object algorithm
reset	Reset internal states of System object
release	Release resources and allow changes to System object property values and input characteristics

Use the following functions to connect to, configure, and control your NI USRP radio device. The diagram shows the call sequence.

1. Create the usrp System object with a radio setup configuration or radio object that you specify with the radio input argument. Set properties that you apply to configure the radio front end settings in a later step.

2. Use the programFPGA and describeFPGA functions to program the FPGA on the radio with your custom bitstream and describe the DUT interfaces with the hand-off information file. You generate these files are generated in Generate Bitstream and Program FPGA of the targeting workflow.

3. Call setup to connect to the radio, apply the radio front end properties, and validate that the block ID in the bitstream file matches the hand-off information file. You now have a live connection to your radio. You can update tunable properties and connect to your DUT by using the fpga object. You can read or write registers on the DUT by using the readPort and writePort function. This step enables you to start streaming samples into your radio with the DUT ports in a known state.

4. Call the System object as a function or call the step function on the System object to start the radio front end. This step calls setup if you did not do so previously, and then starts requesting streaming samples from the radio front end into the FPGA. Specify the numSamples argument to request a specific number of samples, or stream samples continuously by specifying no input arguments.

5. Call the reset function to stop the radio front end and restore the radio to the initialized state before setup. This stops any ongoing transmit or write operation and flushes the receive buffers. Any streaming connections between the DUT and the radio front end may not be flushed.

6. Call the release function to release the hardware resources. This stops any ongoing transmit or write operation and flushes the receive buffers. Any streaming connections between the DUT and the radio front end might not be flushed.

To use synchronization features, specify a radio object as the input. You can synchronize the radio time on multiple radios after you call the setup function. For more information, see Time Synchronize Operations on NI USRP Radios.

Examples

Connect to NI USRP Radio from MATLAB

Create a usrp System object, specifying a radio setup configuration previously saved in the Radio Setup wizard.

device = usrp("MyRadio")

device = 
  usrp with properties:

          TransmitRadioGain: 10
    TransmitCenterFrequency: 2.4000e+09
           ReceiveRadioGain: 10
     ReceiveCenterFrequency: 2.4000e+09
           DUTInputAntennas: []
          DUTOutputAntennas: []
                  BypassDUT: 0
          BypassPLDDRBuffer: 0
               LoopbackMode: "Disabled"
                 SampleRate: []
            CaptureAntennas: []
           TransmitAntennas: []
       CaptureDDRAllocation: 10000000
      TransmitDDRAllocation: 10000000

Configure the hardware interfaces.

describeFPGA(device,"ModelName_wthandoffinfo.mat"); 

Connect to the radio and apply radio front end properties.

setup(device);

Configure NI USRP Radio Device and Program FPGA

Create a usrp System object, specifying a radio setup configuration previously saved in the Radio Setup wizard.

device = usrp("MyRadio")

device = 
  usrp with properties:

          TransmitRadioGain: 10
    TransmitCenterFrequency: 2.4000e+09
           ReceiveRadioGain: 10
     ReceiveCenterFrequency: 2.4000e+09
           DUTInputAntennas: []
          DUTOutputAntennas: []
                  BypassDUT: 0
          BypassPLDDRBuffer: 0
               LoopbackMode: "Disabled"
                 SampleRate: []
            CaptureAntennas: []
           TransmitAntennas: []
       CaptureDDRAllocation: 10000000
      TransmitDDRAllocation: 10000000

Configure your radio with the DUT interfaces described by the hand-off information file and initialize the sample rate on the radio and any DUT input or output antennas. The model this file describes has one data streaming input from the radio to the FPGA, so requires one DUT input antenna.

programFPGA(device,"myBitstream.bit","myDeviceTree.dts"); 

Loading bitstream to FPGA...
Loading bitstream to FPGA is now complete.

Configure Hardware Interfaces on NI USRP Radio Device

Create a usrp System object, specifying a radio setup configuration previously saved in the Radio Setup wizard.

device = usrp("MyRadio")

device = 
  usrp with properties:

          TransmitRadioGain: 10
    TransmitCenterFrequency: 2.4000e+09
           ReceiveRadioGain: 10
     ReceiveCenterFrequency: 2.4000e+09
           DUTInputAntennas: []
          DUTOutputAntennas: []
                  BypassDUT: 0
          BypassPLDDRBuffer: 0
               LoopbackMode: "Disabled"
                 SampleRate: []
            CaptureAntennas: []
           TransmitAntennas: []
       CaptureDDRAllocation: 10000000
      TransmitDDRAllocation: 10000000

Configure your radio with the DUT interfaces described by the hand-off information file and initialize the sample rate on the radio and any DUT input or output antennas. The model this file describes has one data streaming input from the radio to the FPGA, so it requires one DUT input antenna.

describeFPGA(device,"ModelName_wthandoffinfo.mat"); 

Display the initialised radio properties for a DUT.

device

device = 
  usrp with properties:

          TransmitRadioGain: 10
    TransmitCenterFrequency: 2.4000e+09
           ReceiveRadioGain: 10
     ReceiveCenterFrequency: 2.4000e+09
           DUTInputAntennas: "DB0:RF0:RX1"
          DUTOutputAntennas: []
                  BypassDUT: 0
          BypassPLDDRBuffer: 0
               LoopbackMode: "Disabled"
                 SampleRate: 250000000
            CaptureAntennas: []
           TransmitAntennas: []
       CaptureDDRAllocation: 10000000
      TransmitDDRAllocation: 10000000

Configure NI USRP Radio Device, Program FPGA, and Stream Samples

Create a usrp System object, specifying a radio setup configuration previously saved in the Radio Setup wizard.

device = usrp("MyRadio");

Set the baseband sample rate.

device.SampleRate = 250e6;

Program the FPGA with your bitstream and configure the hardware interfaces.

programFPGA(device,"myBitstream.bit","myDeviceTree.dts");

Loading bitstream to FPGA...
Loading bitstream to FPGA is now complete.

describeFPGA(device,"ModelName_wthandoffinfo.mat"); 

Connect to the radio and apply radio front end properties.

setup(device);

Call the usrp System object as a function to start the radio front end. Request a continuous stream of samples by specifying no input arguments.

device();

Release the hardware resources.

release(device);

Configure NI USRP Radio Device and Retrieve Captured Data

Create a usrp System object, specifying a radio setup configuration previously saved in the Radio Setup wizard.

device = usrp("MyRadio");

Program the FPGA with your bitstream and configure the hardware interfaces.

programFPGA(device,"myBitstream.bit","myDeviceTree.dts");

Loading bitstream to FPGA...
Loading bitstream to FPGA is now complete.

describeFPGA(device,"ModelName_wthandoffinfo.mat"); 

Specify a capture antenna on the radio and memory allocation in the PL DDR buffer.

captureLength = 1000;
device.CaptureAntennas = "DB0:RF1:RX1";
device.CaptureDDRAllocation = captureLength;

Connect to the radio and apply radio front end properties.

setup(device);

Call the usrp System object as a function to start the radio front end. Request captureLength samples.

device(captureLength);

Retrieve captureLength samples of captured IQ data from the radio at the default center frequency and baseband sample rate.

[data,dataLength] = capture(device,captureLength);

Confirm that all requested samples were retrieved from the radio.

isequal(dataLength,captureLength)

ans = logical
   1

Configure NI USRP Radio Device and Transmit Waveform

Create a usrp System object, specifying a radio setup configuration previously saved in the Radio Setup wizard.

device = usrp("MyRadio");

Program the FPGA with your bitstream and configure the hardware interfaces.

programFPGA(device,"myBitstream.bit","myDeviceTree.dts");

Loading bitstream to FPGA...
Loading bitstream to FPGA is now complete.

describeFPGA(device,"ModelName_wthandoffinfo.mat"); 

Specify a transmit antenna on the radio and transmitLength samples of memory allocation in the PL DDR Buffer..

transmitLength = 1000;
device.TransmitAntennas = "DB0:RF0:TX/RX0";
device.TransmitDDRAllocation = transmitLength;

Connect to the radio and apply radio front end properties.

setup(device);

Generate a random transmit waveform.

txWaveform = complex(randn(transmitLength,1),randn(transmitLength,1));

Transmit the generated waveform continuously.

transmit(device,txWaveform,"continuous");

Stop the continuous transmission after 5 seconds.

pause(5);
stopTransmission(device);

Version History

Introduced in R2024a

R2025a: Schedule start time for streaming samples from radio

You can now schedule the start time for streaming samples from the radio. Specify the StartTime name-value argument when you call the System object as a function. Alternatively, specify the name-value argument when you call the step function.

To specify the blocking behavior of the streaming operation, use the Background name-value argument.

R2025a: Create usrp object with radio object

You can now use a radio object as the radio input argument when you create a usrp object.

R2025a: Support for USRP E320 radios

You can now use the usrp System object to control a USRP E320 radio with a custom algorithm deployed to the FPGA using the Target NI USRP Radios Workflow.

R2024b: Query DUT clock frequency

You can now use the DUTClockFrequency property to query the clock frequency of the DUT in your deployed design.