Abstract: A nonlinear circuit is investigated, which is characterized by high effeciency, simple and reliable construction, and large tuning frequeney range. For the circuit operating in AC and saturation condition, a mathematical model of the ferrites as the nonlinear inductance element is built up. Along with the exp-erimental work done on the circuit, the frequency conversion characteristics of the nonlinear circuit, the limit of the frequency multiplication, and the power output are discussed by means of compute-aided analysis. Computed results by computer are compared with the experimental ones.