Signal Analysis and SIGINT GUI using MATLAB

DSP Tools developed a real-time data interface that streamed data from a DSP board over 100BaseT Ethernet using TCP/IP to a PC application. From the PC we used a DLL to pass the data stream to our MATLAB program, using the high-powered mathematical environment for signal analysis, demodulation, protocol analysis, protocol decoding and data visualization.

The MATLAB GUI provided the user with the tools needed to determine the modulation parameters of each intercepted signal. It used MATLAB's powerful 2D and 3D surface plotting features to allow the operator to visualize the underlying signal characteristics. We used MATLAB's extensive library of numerical functions to determine the modulation type and parameters. The resulting values were used to select and configure one of our software demodulators to extract the symbol stream. Included in the demodulators were the usual symbol timing and carrier recovery loops.

Using autocorrelation and other numerical techniques, we determined the framing pattern of the data to select the proper protocol decode algorithm. Among the protocol algorithms implemented were Automatic Link Establishment, SITOR, and the three television standards.

By interfacing MATLAB to Microsoft Word using another DLL, we were able to use Unicode to display decoded text that used foreign character sets, including right to left reading scripts such as Arabic.