Reducing Offset and Bias Instability in Lorentz Force Magnetic Sensors Through Bias Chopping

In this paper, we describe a method for reducing offset and offset-related 1/f (flicker) noise in micromechanical resonator-based Lorentz force magnetometers by chopping the dc bias voltage applied to the resonator. This 1/f noise is shown to determine the stability of the sensor's output at long averaging times. The magnetometer is operated at a 40-Hz frequency offset from its 62.88-kHz resonant ...