frequency-domain analysisaccelerometersspectral analysisposition controlvibration measurementcalibrationfield programmable gate arraysfast Fourier transformsmechanical engineering computingvibration detection sensorPSDvibrating targetexternal vibrationsdetected vibration dataself-vibration techniqueADXL-345 three-axis accelerometerstandard Bruel &Kjaer vibration measurement systempiezoelectric accelerometerK accelerometermeasurement techniqueFFT amplitudescalibrated noncontact vibrational harmonics measurementMEMS accelerometerFFT analysisvibrational harmonics measurement systemposition sensitive detectorfrequency-domain vibrational analysisvibration signalspectral analysis