Software Radio Testbed


Description

Our software radio testbed has been implemented as a set of components written in C and C++. These components can be assembled to form a communications system. We have implemented the following receivers using our components:


Hardware

Our receiver hardware consists of a minimal radio front-end receiver, an IF amplifier and a high speed A/D converter.

The A/D converter digitises a 10.7MHz IF and performs all remaining processing in real-time on a PC. Although a RTOS is not being used, real-time processing targets for this receiver are achieved

Our transmitter system is under development. This consists of a high speed D/A converter and with an up-conversion module that can generate signals in multiple bands of interest.


Software

We have implemented our system on Windows 2000. Our system consists of a set of software radio components built from optimised signal processing libraries. These components can be assembled dynamically to create the desired receiver. We have also implemented some components that allow the analysis and recording of data about the software radio system. This has proved an invaluable resource when developing and testing new modulation schemes.


Example

The following screenshot shows a real-time power spectrum display of a demodulated FM signal.
This picture outlines the different components of the FM signal.

This spectrum display component can be inserted anywhere in the communications system to monitor the frequency content of signals at this point. For example, this screenshot shows the frequency content of the signal when it is inserted after audio filtering of the mono component of the signal.

This screenshot shows the spectrum of the digitised 10.7 MHz IF.

Click here to listen to a sample of demodulated broadcast FM.



Related Publications

Mackenzie, P., Doyle, L., O'Mahony, D.& Nolan, K., Software Radio on General-Purpose Processors, in Proceedings of the First Joint IEI/IEE Symposium on Telecommunications Systems Research, Dublin, November 27th, 2001

More Publications


Mail me if you have any questions or comments.


Last modified: 12th December 2001