Reduction of second order distortion in real time

A radio receiver, comprising:

• a local oscillator;
• a first mixer, configured to mix an input signal with a local oscillator signal from the local oscillator to generate an I component of a received radio signal;
• a second mixer, configured to mix the input signal with a phase shifted local oscillator signal to generate a Q component of the received radio signal;
• where the I and Q components of the received signal have a receive bandwidth;
• a processor programmed to:
• compute an estimate of second order distortion components as a power of the I and Q components between approximately the receive bandwidth and twice the receive bandwidth of the received radio signals;
• and
• adjust an operational parameter of the radio receiver to reduce the estimate of second order distortion components.

A radio receiver, comprising:

• a local oscillator;
• a first mixer, configured to mix an input signal with a local oscillator signal from the local oscillator to generate an I component of a received radio signal;
• a second mixer, configured to mix the input signal with a phase shifted local oscillator signal to generate a Q component of the received radio signal;
• where the I and Q components of the received signal have a receive bandwidth;
• a programmed processor;
• one or more digital to analog converters coupled to the processor and configured to convert digital control signals from the processor to a voltage that sets a bias level of one or both of the first and second mixers;
• where the processor is programmed to:
• compute an estimate of second order distortion components as a power output of the I and Q components between approximately the receive bandwidth and twice the receive bandwidth of the received radio signals;
• and
• adjust an operational parameter of the radio receiver to reduce the estimate of second order distortion components.