Differential amplifier with reduced even order non-linearity and associated methods

A differential amplifier having reduced even-order non-linearity comprising:

• a differential amplifier having a differential input port and a differential output;
• and
• an analog voltage compensation circuit comprising a voltage source coupled to said differential input port and a feedback loop having a low-pass response coupled between said differential output and said differential input port, wherein the analog voltage compensation circuit provides an analog compensation voltage to the differential input port so as to reduce the imbalance in the differential amplifier;
• wherein said feedback loop comprises a current amplifier coupled between said different output and said differential input port.

A method for reducing even-order non-linearity in a bandpass differential amplifier having first and second input ports and a differential output, the method comprising the steps of:

• applying a first bandpass signal to the first input port;
• applying a second bandpass signal to the second input port;
• applying a common mode reference voltage to the first and second input ports;
• sensing the response of the differential amplifier to the common mode reference voltage;
• and
• applying a differential compensation voltage across the first and second input ports to decrease any imbalance in the differential amplifier.

A system for reducing even-order non-linearity in an unbalanced bandpass differential amplifier having first and second input ports and a differential output comprising:

• means for applying a first bandpass signal to the first input port;
• means for applying a second bandpass signal to the second input port;
• means for applying a common mode reference voltage to the first and second input ports;
• means for sensing the response of the differential amplifier to the common mode reference voltage;
• and
• means for applying a differential compensation voltage across the first and second input ports to decrease any imbalance in the differential amplifier.