UNTETHERED ACTIVE PEN AND A METHOD FOR COMMUNICATING WITH A CAPACITIVE SENSING DEVICE USING THE UNTETHERED ACTIVE PEN

摘要

A method for communicating with a capacitive sensing device using an untethered active pen. The method includes capacitively receiving a capacitive sensing signal at a capacitive receiving unit of the untethered active pen. The capacitive sensing signal is output from the capacitive sensing device. In addition, the method includes determining a first frequency and a first phase associated with the capacitive sensing signal. Moreover, the method includes transmitting at a second frequency and a second phase an amplified active pen signal at the capacitive sensing device from the untethered active pen. The amplified active pen signal has a second frequency and a second phase that correspond to the first frequency and the first phase.