A method for determining the signal-to-noise ratio of sensors by spectral analysis

Often the dynamic performance of sensors has to be evaluated. For this, figures of merit such as total harmonic distortion (THD) and signal-to-noise ratio (SNR) are useful. Several methods for analysing analog sensor output after sinusoidal stimulation are compared. A method for determining the SNR of an analog sensor is proposed by which the sensor is stimulated sinusoidally, its output sampled, subjected to a FFT and the resulting spectrum analysed to obtain the sensor's SNR value. An experimental set-up for testing displacement sensors is also described. By adapting the outlined measurement method to different sensors the SNR is determined for a number of distance, velocity and acceleration sensors such as eddy current, differential transformer, strain gage and capacitive sensors and compared with the results of interferometric measurements on the displacement actuator.