Closed loop calibration by frequency separation

A calibration system, configured to calibrate a transceiver having a transmitter and a receiver, comprising:

• a transmitter mixer;
• a transmitter local oscillator operatively connected to the transmitter mixer;
• a receiver mixer;
• a receiver local oscillator operatively connected to the receiver mixer;
• and
• calibration circuitry operatively connected to the transmitter local oscillator and the receiver local oscillator, the calibration circuitry configured to:
• control one or more transceiver components to connect an output of the transmitter to an input of the receiver;
• control the transmitter local oscillator to provide a transmitter local oscillator signal having a transmitter local oscillator frequency (fTXLO) to a transmitter mixer to cause the transmitter mixer to upconvert a test signal having a baseband frequency (fBB) to generate an output signal;
• control the receiver local oscillator to provide a receiver local oscillator signal having a receiver local oscillator frequency (fRXLO) to the receiver mixer to cause the receiver mixer to downconvert the output signal of the transmitter mixer to generate a calibration signal;
• wherein the receiver local oscillator frequency is separated from the transmitter local oscillator frequency by a nonzero intermediate frequency (fIF);
• and
• calibrate the transceiver based at least on the calibration signal.

A transceiver, comprising:

• a transmitter having an output;
• a receiver having an input;
• and
• calibration circuitry, coupled to the transmitter and the receiver, configured to control one or more transceiver components to connect the output of the transmitter to the input of the receiver;
• a receiver local oscillator coupled to and controlled by the calibration circuitry to provide a receiver local oscillator signal having a receiver local oscillator frequency (fRXLO) to a receiver mixer;
• a transmitter local oscillator coupled to and controlled by the calibration circuitry to provide a transmitter local oscillator signal having a transmitter local oscillator frequency (fTXLO) to a transmitter mixer;
• wherein the receiver local oscillator frequency is separated from the transmitter local oscillator frequency by a nonzero intermediate frequency (fIF);
• wherein the calibration circuitry is configured to:
• control the transmitter mixer to upconvert a test signal having a baseband frequency (fBB),
• control the receiver mixer to downconvert the output signal of the transmitter mixer to generate a calibration signal, and
• calibrate the transceiver based at least on the calibration signal.