Separation of the nonlinear source-pull from the nonlinear system behavior

In this paper, we describe a measurement technique to identify a nonlinear system in the presence of nonlinear source-pull. Models identified with continuous-wave measurement data are not generalizable when nonlinear source-pull is present. This is demonstrated on measured data and compared with the performance of the proposed technique. The method is based on two-tone signals with very close frequencies that excite the system at the fundamental and harmonic frequencies. By varying the phase relation between the beat components, the system´s nonlinear behavior is separated from the nonlinear source-pull. Note that such excitations can be generated using commercially available synthesizers with single-sideband in-phase-quadrature modulation options.