For the purpose of approximate visual vibration displacement evaluation at low frequencies (not more than 16 Hz) one can use a sticker with two curves forming acute angle.
The essense of the method is the interpolation of the curves during vibration tests perfomance. At the frame frequency over 16 Hz visual perception of separate frames becomes impossible – one can see only stable action. Besides, human vision allows to detect only the extreme positions of the shaker table, since at this moment the displacement speed is almost equal to zero value. Points of the curves located at the distance equal to double value of the displacemt will periodically interpolate in the extreme positions of the vibration table, thus forming a clear picture against a fuzzy background.
The picture was taken during ВС-112 accelerometer test by means of its comparative measurement with a sample vibration sensor (АР10) on a shaker of ВС-133 type. Integrated generator of FFT spectrum analyzer ZET 017 was used for power supply to the shaker system. Vibration displacement value has also been controlled by “Vibration meter” Software application.