A model-agnostic technique for simulating per-element distortion contributions

The nonlinearity of an element can be altered while retaining the original operating point and first-order terms by appropriately combining two instances of the nonlinear element with complementary scaling factors for incremental voltages above the operating points. Per-element distortion contributions in a circuit can then be determined by altering the nonlinear terms by known factors and simulating the output distortion in each case. This technique can be used in a standard circuit simulator with the appropriate nonlinear device models but requires no knowledge of the device model details on the part of the circuit designer. The technique is demonstrated by applying it to a common source amplifier with a nonlinear load and a two stage fully differential opamp.