Amplifier linearisation through the use of special negative linear feedback

The paper presents three new amplifier circuits that use a special type of linear negative feedback to efficiently compensate their nonlinearities. The Volterra transfer functions of each amplifier were found by means of a structural method analysis of weakly nonlinear systems, based on the joint application of the Volterra-Wiener theory for nonlinear systems and the structural theory for linear ones. The necessary conditions for optimising the linear behaviour of the special feedback amplifiers were obtained. With these conditions, the amplifiers only compensate second- and third-order nonlinearities. Meanwhile the linear gains do not suffer the typical reduction caused by the conventional feedback. In addition, experimental realisations of the high linearity amplifiers were tested to validate theoretical results and demonstrate the practical importance of these new structures in some applications