Analysis and Modelling of Mixed-Data Systems with Frequency Translation using Multisine Excitations

In mixed-data systems, such as switched-capacitor circuits, several conversions between continuous and discrete-time occur by samplers and zero-order hold interpolators. These circuits exhibit frequency translations (aliasing) when sampling the continuous-time input signal, that does not obey the Shannon-Nyquist sampling theorem. The concept of multisine excitation signals and the best-linear approximation are extended to estimate both the linear behaviour and the nonlinear distortions of these mixed-data systems, including the frequency translations. The proposed technique is illustrated on both simulations and measurements of a switched-capacitor filter.