Nonlinear Co-Site Interference Measurement

Co-located, high power RF transmitters create interference for out-of-band neighboring receivers through nonlinear intermodulation. Diverse, frequency-agile radios complicate compatibility testing by requiring a broad array of test equipment and engineering expertise to deliver robust quality of service. A new test system in development, the Nonlinear Automated Measurement System (NAMS), is presented to address the challenge of automated testing over the broad range of transmit and receive bands used by current and future radio-dense military platforms. The current NAMS hardware prototype is shown to achieve broadband, high dynamic range performance through the use of software-defined analog signal cancellation and linear system design. A predistortion canceller in development has the potential to further expand the state-of-the-art measurement capability.