Reduction of second-order non-linear distortion in a wideband communication system

A distributed antenna system comprising:

• a first non-linear circuit stage, wherein the first non-linear circuit stage applies an initial second-order non-linear modification to an input signal to provide a first non-linear signal, the initial second-order non-linear modification having an initial first order component and an initial second-order distortion;
• one or more intermediate circuit stages coupled to the first non-linear circuit stage to receive the first non-linear signal, wherein the one or more intermediate circuit stages apply at least a first order modification to the first non-linear signal to generate a modified non-linear signal, the first order modification has an intermediate first order component, and wherein the modified non-linear signal is inverted with respect to the input signal;
• and
• a second non-linear circuit stage coupled to one of the one or more intermediate circuit stages to receive the modified non-linear signal, wherein the second non-linear circuit stage applies an additional second-order non-linear modification to the modified non-linear signal to output an output signal, the additional second-order non-linear modification having an additional first order component and an additional second-order distortion, wherein a ratio of the initial second-order distortion and the initial first order component equals a ratio of the additional second-order distortion and the additional first order component multiplied by an adjustment factor such that second-order distortion is substantially removed from the output signal and wherein the adjustment factor is equal to a ratio of the initial first order component and the intermediate first order component.

A system for reducing second-order distortion in a wideband system, the system comprising:

• a first non-linear circuit stage, wherein the first non-linear circuit stage applies an initial second-order non-linear transfer function to an input signal to provide a first non-linear signal, the initial second-order non-linear transfer function having an initial first order component and an initial second-order distortion;
• one or more intermediate circuit stages coupled to the first non-linear circuit stage to receive the first non-linear signal, wherein the one or more intermediate circuit stages apply at least a first order transfer function to the first non-linear signal to generate a modified non-linear signal, the first order transfer function has an intermediate first order component;
• and
• a second non-linear circuit stage coupled to one of the one or more intermediate circuit stages to receive the modified non-linear signal, wherein the second non-linear circuit stage applies an additional second-order non-linear transfer function to the modified non-linear signal to output an output signal, the additional second-order non-linear transfer function having an additional first order component and an additional second-order distortion, wherein a ratio of the initial second-order distortion and the additional first order component multiplied by an adjustment factor equals a ratio of the initial second-order distortion and the initial first order component such that the first simplifier stage, the one or more intermediate circuit stages, and the second non-linear circuit stage produces an overall second-order distortion in the output signal that is lower than the either of the initial second-order distortion or the additional second-order distortion, and wherein the adjustment factor is equal to a ratio of the initial first order component and the intermediate first order component.