wiki:Tutorials/k0SDR/Tutorial06

Transmitting wideband signals using USRP X310 and wiserd

Table of Contents

  1. SDR Tutorials
    1. Working with USRP2 - Universal Software Radio Peripheral
      1. Description
      2. Hardware / Software Resources utilized
      3. Set up
      4. Usage
      5. Capture waveform and record to file & add time-domain plot of waveform
      6. Troubleshooting
    1. Simple radio example with GNURADIO benchmark scripts
      1. Description
      2. Hardware / Software Resources utilized
      3. Set up
      4. Running GNU Radio benchmark scripts
      5. Outputs from transmitter and receiver
      6. Troubleshooting
    1. Simple radio example with GNURADIO benchmark scripts (OEDL)
      1. Description
      2. Hardware / Software Resources utilized
      3. Set up
      4. Running OEDL script and viewing results
      5. OEDL script
    1. OFDM radio example with GNURADIO benchmark scripts
      1. Description
      2. Hardware / Software Resources utilized
      3. Set up
      4. Running OEDL script
    1. Spectrum sensing with USRP2 and wiserd
      1. Description
      2. Hardware / Software Resources utilized
      3. Set up
      4. Generate signal source file using octave
      5. Set up transmitting node
      6. Set up receiving node(s)
    1. Spectrum sensing with USRP2 and wiserd (OEDL and OML)
      1. Description
      2. Hardware / Software Resources utilized
      3. Transmit predefined tone
      4. Record spectrum data to an OML file
      5. Performing the experiment using OEDL
    1. Transmitting wideband signals using USRP X310 and wiserd
      1. Description
      2. Transmitting a signal using wiserd
      3. Creating the signal
    1. Running DSC match script from the grid console
    1. Working with GNURadio and Nutaq ZeptoSDR
      1. Description
      2. Set up
      3. Run the GRC scripts
    1. Realtek 2832 EZCap - A Frugal SDR
      1. Prereqs
      2. A cheap spectrum analyzer
    1. MacSwitch (Obsolete)
      1. Prerequisites
      2. Start Mac Switch
    1. Zynq-based WISER platform - Start-up test
      1. Description
      2. Hardware / Software Resources utilized
      3. Set up
      4. Loading the Zedboard
      5. Running a start up test
    1. Zynq-based WISER platform - Spectrum Sensing
      1. Description
      2. Hardware / Software Resources utilized
      3. Set up
      4. Start spectrum sensing
    1. Zynq-based WISER platform - Spectrum sensing with multiple nodes (OEDL)
      1. Description
      2. Hardware / Software Resources utilized
      3. Spectrum sensing with an OEDL script
    1. Zynq-based WISER platform - Building the Firmware
      1. Description
      2. Getting the FPGA source code
      3. Building the FPGA design
      4. Building ARM core software
    1. Nutaq - PicoSDR start-up and configuration
      1. Description
      2. Set up
      3. Launch demo scripts
    1. Multi channel sample collection with x310
      1. Description
      2. Set up
      3. Collect samples
    1. Getting started with RFNoC X310
      1. Description
      2. Set up
      3. Find USRP X310s
      4. Program the FPGA
    1. Multi Channel Sample Processing & Visualization
      1. Hardware / software resources utilized
      2. Receive multi channel signal for processing and plotting
      3. Transmit a signal using a single usrp
    2. Plot the IQ Constellation of received signal
      1. Multi-channel Uhd STreamer (MUST)
      2. Description
      3. How it works (without going into the source-code :-D
      4. Source code & compilation
      5. Hardware interface application
      6. XML file
      7. Command server
      8. Usage Example
      9. Signal handler applications
      10. Tutorials
    1. Using two RFNoC streams simultaneously on a single USRP device
      1. Description
      2. Set Up
      3. Running the Simulation
    1. Using 2 transmit or 2 receive antennas simultaneously
      1. Description
      2. Set Up
      3. Running the Experiment
    1. Generate random transmissions emulating Primary Transmitters
      1. Description
      2. Set Up
      3. Running the Experiment

Description

In this tutorial we will describe how to create and transmit a wideband signal using wiserd on a USRP X310 radio device equipped node.

Transmitting a signal using wiserd

Wiserd producer module signal_from_file can be used for transmission of a custom signal. The signal needs to be saved in a binary file, containing 32bit float values of I and Q samples of the signal. To use wiserd on a USRP X310 equipped node (e.g. node3-1 on grid.orbit-lab.org), we can use the ubuntu-14-04-64bit-sdr.ndz image, which has the latest version of wiserd installed in the root's home directory. After the node is imaged and accessed, we need to make an additional adjustment in order to work with USRP X310 by running 'ifconfig eth2 mtu 9000' on the node (note that this should not be done on nodes with USRP 2 or N210). After running wiserd, we can use the following commands in order to set the required parameters (in this case we assume the central transmission frequency of 700 MHz, signal bandwidth of 200 MHz, transmitter gain of 20 dB and our signal is stored in the signal.bin file):

--uhd_tx_freq 700e6 --uhd_tx_rate 200e6 --uhd_tx_gain 20 --tran_wavefilename signal.bin --addmodule signalfromfile

To stop the transmission we use

--delmodule signalfromfile

Creating the signal

The signal can be created in Matlab. To create a desired shape of signal in frequency domain, we suggest creating the shape and performing the ifft function on it to get the I and Q time samples. After we have the signal as a complex 32bit float array, we can save it to a file using the following function:

function saveToWiserdFile( signal, filename )
    fid = fopen(filename,'w');
    fwrite(fid, [real(signal); imag(signal)], 'float32');
    fclose(fid);
end

Note that the output power of USRP X310 is 100 mW. The signal I and Q time samples represent voltages, and use the impedance of 50 Ω to normalize the signal power. Any signal with power higher than 100 mW will not be transmitted properly.

Last modified 2 years ago Last modified on 06/12/15 15:54:59