Adaptive Same Frequency Repeater (SFR) breadboard improvements

This report documents the technical effort conducted under Amendement P00003 to Contract F30602-74-C-0242. It presents the results of modifications to the real time, nonsampling, Same-Frequency Repeater breadboard equipment originally constructed under the above contract effort. The SFR is capable of relaying various types of analog and digital signals using coherent interference cancellation techniques to prevent oscillation. The main thrust of this effort was to increase the forward gain from the 67 db obtained in the initial effort to a performance goal of 100 - 120 db. The actual measured forward gain achieved in this follow-on effort was 102db. This improved forward gain was attained through modification of circuits in the breadboard equipment. The basic SFR system structure, and the concepts on which it was predicated remain intact. The results of the initial effort are summarized in RADC-Tr-76-78 entitled, 'Adaptive Same Frequency Repeater SFR) Study'. The modifications that were performed and the performance results obtained in this follow-on effort are discussed in this report. Updated system and circuit diagrams are included as well as a discussion of those technical areas where additional work would further improve SFR equipment performance.