Mems parameter identification using modulated waveforms

A microelectromechanical systems (MEMS) application module comprising:

• a MEMS sensor having a moveable mechanical element configured to be capable of modulation responsive to an electromagnetic signal applied to the moveable mechanical element, and further comprising a sense contact configured to provide as an output an electromagnetic output signal corresponding to motion of the moveable mechanical element;
• a control circuit in electrical communication with the moveable mechanical element of the MEMS sensor, and configured to provide an electromagnetic input signal comprising a first low-frequency component of a frequency low enough to cause the moveable mechanical element to physically oscillate, and a second high-frequency component of a frequency high enough to not cause oscillation in the moveable mechanical element;
• demodulation circuitry in electrical communication with the sense contact of the MEMS sensor, and configured to demodulate the electromagnetic output signal corresponding to motion of the moveable mechanical element to remove the carrier component, and provide a demodulated signal as a demodulated output;
• a first signal filter in electrical communication with the control circuit, wherein the first signal filter is configured to receive the electromagnetic input signal, remove the higher-frequency signal from the electromagnetic input signal, and provide the filtered lower-frequency signal as an output;
• a second signal filter electrically coupled to the demodulation circuitry, wherein the demodulated signal provided by the demodulation circuitry comprises at least one lower-frequency signal and one higher-frequency signal, and wherein the second signal filter is configured to remove the higher-frequency signal from the demodulated signal and provide the resulting filtered demodulated lower-frequency signal as an output;
• signal evaluation circuitry electrically coupled to the first signal filter and second signal filter and the control circuit, wherein the signal evaluation circuitry is configured to receive the filtered lower-frequency signal from the first signal filter and filtered demodulated lower-frequency signal from the second signal filter, compare at least one characteristic of those signals, and provide a characteristic signal indicative of the at least one compared characteristic to the control circuit.

A method of determining a parameter of a MEMS sensors in a system, comprising:

• generating an input signal including at least one high-frequency component selected to not cause physical oscillation of a moveable mechanical element of a MEMS sensor, and one low-frequency component selected to cause physical oscillation of a moveable mechanical element of a MEMS sensor;
• providing the input signal to a MEMS sensor comprising at least one moveable mechanical element to cause a modulated output signal comprising high and low frequency components to be provided from the MEMS sensor;
• de-modulating the modulated output signal provided by the MEMS sensor;
• filtering the de-modulated output signal to remove the high frequency components;
• and,
• evaluating the de-modulated, filtered signal to determine at least one characteristic of the MEMS sensor.