Understanding the Nonlinearity of a Mixer Using Multisine Excitations

In this paper, a measurement technique is proposed to verify whether the "nonideal nonlinearities" of mixers are introduced before or after the ideal multiplier. To prove the concept of the proposed approach, simulations are used to show how the system reacts on a special odd multisine excitation. This allows to predict the contributions of the nonideal nonlinearities in the output spectrum of the mixer. A real mixer is then excited with a special odd multisine and measured with a 2-port large signal network analyzer (LSNA). The measurement results are compared to the simulations to validate this technique, which technique allows to get more insight in the nonideal nonlinear behavior of mixers