“…Some of these include circuits with analog output from the company Analog Devices such as ADXL335 [16], [63]- [65], [72], [73], [76], ADXL356 [66], ADXL322 [68], and ADXL203 [77]; those of NXP USA Inc., such as MMA6270QT of [62], and MMA7260Q [43]. Various researchers have also employed those having digital output, some from Analog Devices: ADXL345 [16], [63], [65], [67], [74], and ADXL355 [73]; those of NXP which includes the MMA8451Q [75], and the FXLS8471Q [70]; the LSM6DS3TR of STMicroelectronics [71]; and TDK's MPU-6050 [63], [65], [78]. One of the mathematical tools to analyze oscillations consists of applying to the raw signals of MEMS accelerometers the discrete Fourier transform (DFT), using the FFT (Fast Fourier Transform) algorithm [62], [70], [72], [73], [75]- [78].…”