A Spread-Spectrum Analysis and Design Laboratory System

Spread-Spectrum waveforms are used commonly for Anti-Jam (A/J) and Low-Probability-of-Intercept (LPI) applications, but their effectiveness is difficult to assess owing to the diversity of system parameters and to various user requirements. This paper describes a spread-spectrum analysis and design laboratory system consisting of a software analysis subsystem and a hardware breadboarding facility. The laboratory system provides both A/J and intercept threat analysis capabilities. Through figure-of-merit expressions, design trade-offs can be conducted and design verifications made by breadboard experiments. As the number of military spread-spectrum systems increases in the future, the conventional analysis and design approach will not be flexible enough to accommodate the growing number of candidate waveforms. This laboratory system provides a cost-effective and flexible alternative. Examples presented in the paper describe the analysis and design procedures and the results for a spread-spectrum communication system to combat various intercept threats including radiometers (wideband and channelized), chip-rate detectors, and hop-rate detectors. A unique laboratory breadboard hierarchical approach is also presented, where multiple waveform generation is possible through a basic communications modem. Most MFSK, FH, and PN waveforms and their combinations can be generated by the hierarchical structure.