Identification of double-valued nonlinearities from their harmonic response

A method is presented for determining an equation for a double-valued nonlinearity from a measurement of its response to a sinusoidal input. It is shown that the nonlinearity can be represented as a series in Cheby¿shev polynomials of the first and second kind with argument dependent on the input magnitude. The coefficients of the Cheby¿shev-polynomial terms in the series are the measured in-phase and quadrature output-harmonic magnitudes.