Quadrature Bridge for Capacitor Non-linearity Measurement

A bridge is described that can measure capacitor harmonic distortion down to –160 dB. The requirements for the input signal generator are greatly relaxed by the action of a servo loop that produces a quadrature drive signal, while simultaneously suppressing common-mode signals at the bridge output. Measurement results were compared with simulations, leading to an estimation of the capacitor non-linearity model.