A capacitive sensing apparatus is disclosed. In some examples, the capacitive sensing apparatus includes a sensor control system configured to: during a first scan of the sensor array: transmit a first alternating current (AC) signal concurrently with a second alternating current (AC) signal to the sensor array, transmit the first AC signal to the first electrode of the sensor array, measure a self capacitance at the first input location, and transmit the second AC signal to the second electrode of the sensor array without measuring a self capacitance at the second input location, and during a second scan of the sensor array: transmit the first AC signal concurrently with the second AC signal to the sensor array, transmit the first AC signal to the first electrode of the sensor array without measuring the self capacitance at the first input location, and measure the self capacitance at the second input location.