Adaptive linearization technique for communication building block

A circuit for linearizing an input signal, comprising:

• a main circuit that receives the input signal and outputs a main output signal;
• a nonlinear auxiliary output signal;
• a combiner coupled to said main circuit and said nonlinear circuit that combines the main signal and the auxiliary signal to yield an output signal;
• and
• a feedback loop that receives a portion of the output signal and outputs a non-linearity feedback signal to said auxiliary nonlinear circuit,
• wherein the feedback loop includes a bandpass filter to pass adjacent or nearby channels of the output signal output from the combiner to determine if spectral leakage occurs in the adjacent or nearby channels.

A method for linearizing an input signal, comprising:

• processing the input signal with a main signal processing circuit;
• processing the input signal with a non-linear circuit;
• combining an output signal of the main signal processing circuit and the non-linear circuit to generate an output signal;
• passing adjacent or nearby channels of the combined output signal through a bandpass filter;
• determining if spectral leakage occurs in the adjacent or nearby channels;
• and
• determining an adjustment to control parameters of the non-linear auxiliary circuit to change one of increase or decrease its non-linearity based on determining if spectral leakage occurs in the adjacent or nearby channels.

A method for improving signal quality in a signal processing system, comprising:

• (a) processing an input signal based on a transfer function H1;
• (b) processing the input signal based on a transfer function H2;
• and
• (c) subtracting the processed signals from steps (a) and (b),
• wherein step (b) includes increasing non-linearity of transfer function H2 by an amount sufficient to substantially suppress at least one predetermined harmonic in the processed signal output from step (a) and at least first- and third-order harmonics in the processed signal output from step (b) when the processed signals are subtracted in step (c), and
• wherein H1(X)=a1X+a3X3 and H2(X)=b1X+b3X3 and X is the transform of x(t), a1xa3<0, b1xb3<0, a1−a3is approximately a1, and b1−b3 is approximately 0.

A system for improving signal quality in a signal processing system, comprising:

• a first signal processing block which modifies an input signal based on a transfer function H1;
• a second signal processing block which modifies the input signal based on a transfer function H2;
• a combiner that combines the processed signals from the first and second signal processing blocks, wherein the second signal processing block increases non-linearity of transfer function H2 by an amount sufficient to substantially suppress at least one predetermined harmonic in the processed signal output from the first signal processing block and at least first- and third-order harmonics in the processed signal output from the second signal processing block when the processed signals are combined by the combiners
• wherein H1(X)=a1X+a3X3 and H2(X)=b1X+b3X3 and X is the transform of x(t), a1xa3<0, b1xb3<0, a1−a3 is approximately a1, and b1−b3 is approximately 0.

A circuit for an initially at least partially nonlinear circuit;

• comprising:
• means for splitting an input signal into a first and second input signal;
• means for determining the effect of the at least partially nonlinear circuit on a predetermined harmonic of said first input signal;
• and
• a unit that receives said second input signal and modifies a second predetermined harmonic of said second input signal in a manner such that if the output of said unit and said at least partially nonlinear circuit are combined, the predetermined harmonic of said first input signal is at least partially suppressed,
• wherein the determining means includes a bandpass filter to a pass adjacent or nearby channels of the combined output signal to determine if spectral leakage occurs in the adjacent or nearby channels.

A circuit for linearizing an input signal x(t), comprising:

• a main circuit that receives the input signal with a main transfer function of approximately H1 and outputs a main signal output;
• a nonlinear auxiliary circuit that receives the input signal and has a nonlinear auxiliary transfer function of approximately H2 and outputs a nonlinear auxiliary signal output, wherein H1(X)=a1X+a3X3 and H2(X)=b1X+b3X3 and X is the transform of x(t), a1xa3<0, b1xb3<0, a1−a3 is approximately a1, and b1−b3 is approximately 0;
• a combiner coupled to said main circuit and said nonlinear auxiliary circuit that combines said main signal and said auxiliary signal to yield an output signal;
• and
• a feedback loop that receives a portion of the output signal and outputs a non-linearity feedback signal to said auxiliary nonlinear circuit,
• wherein said main circuit comprises a linearization circuit.