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Repeated Waveform Transmitter

You can download any signal waveform to the hardware and transmit repeatedly over the air using one of the SDR transmitter System objects for ADALM-PLUTO radio. This feature enables you to use SDR System objects together with the hardware as an RF signal generator. You can create any arbitrary waveform at the baseband in MATLAB® and transmit repeatedly from the hardware. You are not limited by the USB connection or the processing speed of the host computer for signal transmission over the air.

Use this feature to:

  • Transmit signals such as reference signals and radio beacons.

  • Provide waveforms that are continuously transmitted and do not rely on the host for further signal generation.

  • Transmit a fixed waveform at a specific rate until you explicitly stop it.

  • Repeatedly transmit a signal from the hardware by using a targeted transmit bitstream.

To call the repeated waveform transmitter, use the transmitRepeat method, found on System objects for ADALM-PLUTO radios.

Continuously Transmit 100 kHz Complex Tone

Send a complex tone of 100 kHz at a baseband sample rate of 1 MHz.

Generate a waveform.

fs = 1e6;
sw = dsp.SineWave;
sw.Amplitude = 0.5;
sw.Frequency = 100e3;
sw.ComplexOutput = true;
sw.SampleRate = fs;
sw.SamplesPerFrame = 5000; % to meet waveform size requirements
tx_waveform = sw();

Create a System object™ for the ADALM-PLUTO radio and set desired radio settings.

radio = sdrtx('Pluto');
radio.CenterFrequency = 2.415e9;
radio.BasebandSampleRate = fs;
radio.Gain = 0;

Send the waveform to the radio and repeatedly transmit it for 10 seconds.

runtime = tic;
while toc(runtime) < 10
    transmitRepeat(radio,tx_waveform);
end

Stop transmitting the waveform and release the object.

release(radio);

Transmit and Receive on Single Device

You can use the transmitRepeat functionality with normal receive methods to transmit and receive waveform data with single piece of hardware. You can develop receiver algorithms without requiring two boards. Make sure your board is powered on, configured correctly for use with Communications Toolbox™ Support Package for Analog Devices® ADALM-Pluto Radio, and able to send and receive signals.

The general workflow for this feature is:

  1. Generate data for transmitting (see previous section).

  2. Create your receiver design.

  3. Create a transmitter System object.

  4. Call the transmitRepeat method of the transmitter System object.

  5. Set up antennas or loopback.

  6. Run your receiver function.

To see this feature applied, look at and run Image Transmission and Reception Using 802.11 Waveform and SDR (WLAN Toolbox). You can examine the code in the example for ways to receive WLAN signals.

See Also

Related Topics