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Investigation of Radio Frequency Repeater Design Elements for Spread Spectrum Signals, 16-9479

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Principal Investigators
Jeremy Pruitt
Jim Moryl

Inclusive Dates:  06/07/04 - 10/07/04

Background - On Project 16-10335, SwRI developed a breadboard radio frequency (RF) repeater to demonstrate the operational utility of a spread-spectrum repeater for extending the coverage of a Blue Force tracking system. The breadboard RF repeater fell short of meeting the operational range goals and subsequent analysis identified the need for a better understanding of the impact of a bandpass limiter circuit on spread spectrum signals over a range of operating conditions.

Approach - A literature review identified several key papers that contained information contributing to an analytical model of the performance of a bandpass limiter with spread spectrum signals. Laboratory data were collected under a variety of operating conditions using an available spread spectrum transmitter, repeater circuit and spread spectrum receiver. The impacts of various operating conditions and circuit designs were examined and documented in the final report.

Accomplishments - The results of this project identified several design modifications to the breadboard RF repeater circuit. The results confirmed that bandpass limiter architecture is appropriate for a spread spectrum repeater, but additional losses must be accounted for to achieve long-range operation. The results have contributed to the external funding of a follow-on task for the development of a deployment model Blue Force tracking repeater system.

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