US Patent 7324915 Data transmission to a position sensor

A method for transmitting control instructions to a sensor in a position tracking system includes generating a drive signal for driving a field generator. A control signal including the control instructions is superimposed on the drive signal. The field generator is driven with the drive signal, so as to generate a field to be sensed by the sensor. The field is detected at the sensor in order to determine position coordinates of the sensor and to demodulate the control signal so as to extract the control instructions. A functionality of the sensor is controlled based on the extracted control instructions.