first sine wave signal at a first frequency during a first time period a second signal at a second sine frequency during a second time period etc a total of n ac signals at n frequencies may be generated where n is a whole integer the plurality of n signals may be output simultaneously or sequentially by the signal generator 24 the signal generator 24 is in communication with the seat heater electrode element 12 which is configured to generate an electric field in response to the signals from the signal generator 24 the electric field is projected to a location at which an object occupant is to be detected such as the seating area of the seat assembly 10 the impedance of a load 14 affects the voltage response received by the voltage detection circuitry 26 the voltage detection circuitry 26 measures a voltage for each of the n frequencies at the n time periods the measured voltages may depend upon the impedance of the load 14 which may include impedance caused by an occupant and environmental conditions such as humidity moisture and temperature the pods ecu 22 also includes processing circuitry 28 in communication with the voltage detection circuitry 26 the signal processing circuitry 28 may include a processor such as a microprocessor or other digital circuitry the processor 28 is shown including a routine 100 which may be executed by the processor 28 it should be appreciated that the processing circuitry 28 may include a plurality of noise filters not shown and may convert the measured voltages into digital voltage amplitudes the voltage amplitudes are compared to determine if a change in voltage has occurred amongst the plurality of frequencies a change or difference.