Vibration

Not sure about your grammar but if you mean: "do we measure the vibration as a displacement, Velocity, Accelaration?" ... in most vibration measurements, the quantity measured directly is acceleration, then the signal is integrated to obtain the velocity and displacement signal. For instance, to measure the vibration of a rotating shaft, an accelerometer is often attached to the bearing housing. Laser vibrometers (highly expensive!) will measure displacment and use the discreet integration of successive vector samples to calculate the velocity and acceleration of measured points.

There's lots of other types of vibration sensors too, but in general, the measured quantity is acceleration.

Hope that helps

TinTin

"the discreet integration" - i meant differentiation, but my editing time expired