Lockheed Martin engineers used MATLAB® and Simulink to design, model, and simulate the digital channelizer. They then used HDL Verifier™ and Mentor Graphics® ModelSim® to verify, analyze, and visualize the VHDL® implementation in Simulink.
Watson used MATLAB to develop algorithms for the channelizer. As band plans changed, Watson parameterized the algorithms, enabling him to tailor variables to implement a new band plan in a matter of minutes. The ability to perform fast, iterative design changes helped to keep the project on track even in the face of ever-changing requirements.
A second Lockheed Martin engineer used Simulink to develop a hardware-like, full- system model of the digital channelizer based on the MATLAB algorithms. He used delay lines, interleavers, deinterleavers, and other blocks from DSP System Toolbox™ and Communications System Toolbox™ to implement two stages of channelization and two stages of reconstruction, and to manage all the signals between them.
The team also used Simulink to build test-bench wrappers that included signal sources, such as simulated radio frequency/intermediate frequency (RF/IF) signals, and output analysis tools, such as buffered fast Fourier transform displays and spectrogram analyzers.
"The Simulink models documented the design, provided traceability, and enabled us to visualize the outputs of the system as it was operating," Watson notes.
After implementing the design in VHDL, the engineers used HDL Verifier and Mentor Graphics ModelSim to perform a final functional verification of the VHDL implementation at the bit level.
To minimize the effects of radiation upset, the system uses three identical channelizers and then "votes" on the results. Lockheed Martin engineers used HDL Verifier to resolve complex reset condition and clocking issues in the voting system.
Watson used MATLAB to generate test vectors and post-process test results for hardware tests of the system running on Xilinx® Virtex-II 2v6000 FPGAs.
The digital channelizer has been successfully demonstrated in hardware, and is currently undergoing formal tests for flight certification.