Sliding Window and DC Offset Correction Technique for Pulse Doppler Radar Systems

A pulsed DC radar system, comprising:

• a mixer configured to receive an RF oscillation signal, an RF input signal, and a DC offset signal, the mixer providing a mixer output signal that is the result of downconverting the RF input signal with the RF oscillation signal and DC offsetting the result by the DC offset signal;
• a digital-to-analog converter (DAC) that receives a digital DC offset value and provides the DC offset signal;
• an integrating filter coupled to receive the mixer output signal, the integrating filter receiving an integration window timing signal and operating when an integration window is open to produce a filtered output signal;
• a sample-and-hold (SAH) circuit coupled to receive the filter output signal from the integrating filter and providing an SAH signal;
• a comparator coupled to receive the SAH signal and provide a comparator signal indicating whether the SAH signal is above or below zero;
• and
• a controller coupled to the DAC to provide the digital DC offset value and to the integrating filter to provide the integration window timing signal opening and closing the integration window and to the comparator to receive the SAH signal, the controller executing instructions to
• execute an operation state that provides the integration window that is determined from a set of integration windows that is incremented on each transmit pulse and provides a DC offset value associated with the integration window, and
• execute a calibration state that determines calibrated DC offset values for each integration window in the set of integration windows.