GNU Radio and USRP

GNU Radio is a toolkit where digital signal processing blocks are written in C++, and where these are connected to each other with Python. This makes it easy to develop more sophisticated signal processing systems, because you can use blocks already written by others and quickly put them together to a complete system.

Here I will try to put together some guides on what you can do with the toolkit, and how you do it. For a general introduction to GNU Radio and a hello world example look at Exploring GNU Radio.

• How to make a simple GUI with spectrum analyzer and oscilloscope


• How to demodulate FM from a radio wave capture file.


• How to receive Automatic Identification System (AIS) messages used by ships to navigate


• A collection of radio capture samples

USRP

The USRP (Universal Software Radio Peripheral) is a device for getting radio waves into the computer for software processing. The USRP is directly supported by the GNU Radio toolkit. This means that you can write real-world signal processing systems capable of handling radio frequencies easily in real time.

But you do not need to own a USRP to have fun with GNU Radio. You can for example use other's radio wave captures. At the radio amateur KD7LMO's homepage you can find several captures. You can also find some captures here.

A photo of my USRP

• GNURadio Control GUI (Unfortunately not updated to use the new gnuradio code yet) - A graphical user interface for watching what a radio capture file contains, and has the abilitiy to demodulate WFM, FM, AM and SSB by pointing at the signal. It can also control the USRP and demodulate what's coming straight from the air.

• GNU Radio - The home page of GNU Radio. Where you can download the code
• Discuss-gnuradio archive - Where questions are asked and answered
• Ettus Research LLC - Where you can buy the USRP
• GNU Radio Reference - Class Hierarchy
• http://digilander.libero.it/iz2eeq/
• Tools4SDR