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basebandTransceiver

Configure SDR as baseband transceiver

Description

Use the basebandTransceiver object to configure the specified software-defined radio (SDR) as a baseband transceiver to simultaneously transmit and capture IQ waveforms over the air.

This diagram shows a conceptual overview of capturing and transmitting radio signals in Wireless Testbench™ using a radio that you configure with this object. The onboard data buffering ensures contiguous data capture and transmit. The transmission controller enables you to specify continuous or single-shot transmissions.

Arrows appoint the path of the captured and transmit data. The captured data path consists of radio antenna, onboard memory, and MATLAB. The transmit data path consists of MATLAB, onboard memory, transmission controller, and radio antenna.

Creation

Description

example

bbtrx = basebandTransceiver(radio) creates a baseband transceiver object for the specified radio radio.

Note

The object requires exclusive access to radio hardware resources. Before creating this object, clear any existing Wireless Testbench object associated with the specified radio from the workspace.

bbtrx = basebandTransceiver(radio,Name=Value) sets properties using one or more name-value arguments. For example, CaptureDataType="double" sets the data type of the returned captured data to double.

Input Arguments

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Radio setup configuration, specified as a string scalar. To create a radio setup configuration, set up your radio and save your radio setup configuration using the Radio Setup wizard. Call the radioConfigurations function to list all saved radio setup configurations. For more information, see Connect and Set Up NI USRP Radios.

Example: "MyRadio" indicates that you saved a radio setup configuration under the name MyRadio in the Radio Setup wizard.

Properties

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Transmit center frequency in Hz, specified as a positive numeric scalar. The valid center frequency range depends on the radio device.

Radio DeviceCenter Frequency

USRP™ N310

1 MHz to 6 GHz

USRP N320

1 MHz to 6 GHz

USRP N321

1 MHz to 6 GHz

Transmit radio antenna, specified as a string scalar. Use this table to identify a supported radio antenna port on the radio device and the corresponding string constant that you can specify for this property.

Radio DeviceSupported Antenna PortValid String Scalar

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"

Note

When you update this property, the execution time of the next object function call increases by a few seconds.

Data Types: string

Transmit radio gain in dB, specified as a positive numeric scalar. The valid gain range depends on the radio device.

Radio DeviceTransmit Radio Gain

USRP N310

0 dB to 65 dB

USRP N320

0 dB to 60 dB

USRP N321

0 dB to 60 dB

Data Types: double

Capture center frequency in Hz, specified as a positive numeric scalar. The valid center frequency range depends on the radio device.

Radio DeviceCenter Frequency

USRP N310

1 MHz to 6 GHz

USRP N320

1 MHz to 6 GHz

USRP N321

1 MHz to 6 GHz

Data Types: double

Capture radio antenna, specified as a string scalar. Use this table to identify a supported radio antenna port on the radio device and the corresponding string constant that you can specify for this property.

Radio DeviceSupported Antenna PortValid String Scalar

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)
RF1 channel: RX2 port"RF1:RX2"

Note

When you update this property, the execution time of the next object function call increases by a few seconds.

Data Types: string

Capture radio gain in dB, specified as a positive numeric scalar. The valid gain range depends on the radio device.

Radio DeviceCapture Radio Gain

USRP N310

0 dB to 75 dB

USRP N320

0 dB to 60 dB

USRP N321

0 dB to 60 dB

Data Types: double

Data type of the captured data, specified as "int16", "double", or "single". Use this property to set the data type of the captured data that the capture object function returns.

Note

When you update this property, the execution time of the next object function call increases by a few seconds.

Data Types: string

Baseband sample rate in Hz, specified as positive numeric scalar. The object automatically selects the master clock rate available for the radio based on the specified sample rate. Therefore, the valid range for the sample rate depends on the master clock rate available on the radio. The sample rate must be less than or equal to MCR/2 or equal to MCR, where MCR is the master clock rate that the object selects. For more information, see Baseband Sample Rate in NI USRP Radios.

Radio DeviceSample RateMaster Clock Rate

USRP N310

120,471 Hz to 153.6 MHz

153.6e6 (default)

122.88 MHz

125.00 MHz

153.60 MHz

USRP N320

196,078 Hz to 250 MHz

250e6 (default)

200.00 MHz

245.76 MHz

250.00 MHz

USRP N321

196,078 Hz to 250 MHz

250e6 (default)

200.00 MHz

245.76 MHz

250.00 MHz

Note

To update this property, you must stop any ongoing transmission by calling the stopTransmission function on the object. When you update this property, the execution time of the next object function call increases by a few seconds.

Data Types: double

Behavior of the capture object function upon dropped samples, specified as one of these values.

  • "error" — The object function stops with an error message.

  • "warning" — The object function displays a warning message.

  • "none" — The object function ignores dropped samples.

Data Types: string

Object Functions

captureCapture IQ data using baseband receiver or transceiver
transmitTransmit waveform using baseband transmitter or transceiver
stopTransmissionStop transmission from baseband transmitter or transceiver

Examples

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

bbtrx = basebandTransceiver("MyRadio")
bbtrx = 
  basebandTransceiver with properties:

          TransmitRadioGain: 10
    TransmitCenterFrequency: 2.4000e+09
           TransmitAntennas: "RF0:TX/RX"
           CaptureRadioGain: 10
     CaptureCenterFrequency: 2.4000e+09
            CaptureAntennas: "RF0:RX2"
            CaptureDataType: "int16"
       DroppedSamplesAction: "error"
                 SampleRate: 250000000

Set the baseband sample rate.

bbtrx.SampleRate = 122.88e6;

Set the transmit and capture center frequencies.

bbtrx.TransmitCenterFrequency = 2.2e9;
bbtrx.CaptureCenterFrequency = 2.2e9;

Generate random transmit waveform.

txWaveform = complex(randn(1000,1),randn(1000,1));

Transmit the generated waveform continuously with the radio associated with the baseband transceiver object using the default transmit antenna.

transmit(bbtrx,txWaveform,"continuous");

Capture IQ data with the radio associated with the baseband transceiver object using the default capture antenna.

[data,~] = capture(bbtrx,milliseconds(3));

Stop the continuous transmission after data capture is complete.

stopTransmission(bbtrx);

Version History

Introduced in R2022a