“…Rotating machines are present in many industry areas, like machining, turbines, motors, gears, and shafts, and the rotation speed must be under control to prevent unexpected mechanical failures [ 1 ]. Measurement system for instantaneous rotational speed (IRS) can characterize faults in mechanical systems [ 2 ], such as gears [ 3 , 4 , 5 ], engines [ 6 , 7 , 8 ], shaft torsional vibrations [ 9 ], bearings [ 10 , 11 , 12 ], high rotating speed rotating propellers [ 1 ], estimate life cycle of machines, and evaluate their work conditions. Therefore, a reliable measurement system is required to control these parts’ life cycles.…”