Patent ID: 6396327
Filing Date: 2002-05-28
Classification: H04B

Abstract:
A method of applying a desired nonlinear transfer function to an input signal to compensate for undesired distortion of the input signal in a nonlinear device, the method comprising the steps of:splitting the input signal to a first input signal and a second input signal: producing a first output signal by applying a sinusoidal transfer function to the first input signal, comprising the steps of: applying the first input signal to a predistortion circuit that approximates a sinusoidal transfer function, the predistortion circuit having a resistance from a node to an electrical ground through a plurality of shunt elements, wherein each shunt element of the plurality of shunt elements comprises a diode connected in series with a resistive element and a capacitive element to the electrical ground; reducing the resistance from the node to electrical ground through a first shunt element of the plurality of shunt elements for a first predetermined range of positive input signal amplitudes of the input signal; reducing the resistance from the node to electrical ground through a second shunt element of the plurality of shunt elements for a first predetermined range of negative input signal amplitudes of the input signal; reducing the resistance from the node to electrical ground through a third shunt element of the plurality of shunt elements for a second predetermined range of positive input signal amplitudes of the input signal; and reducing the resistance from the node to electrical ground through a fourth shunt element of the plurality of shunt elements for a second predetermined range of negative input signal amplitudes of the input signal; wherein the steps of reducing the resistance to electrical ground produces the sinusoidal transfer functions and combining the first output signal with a multiple of the second input signal to approximate the desired nonlinear transfer function.