Vibrometer University

 

Getting the most out of a laser vibrometer is enhanced by understanding the physics behind the instrumentation and the fundamentals that determine its range of application.

 

 

Vibrometer Video

Polytec Tutorial
PDF Series

Fundamentals

 

Join in a short video journey into vibration measurement and Polytec’s innovative solutions.

 

Download and collect this continued tutorial about laser Doppler vibrometry and other light-based measurement techniques.

 

Learn more about Laser Basics, Vibrometry Basics, Signal Processing and Surface Effects.
 
 

 

 

 

 

Fundamentals

Laser Doppler vibrometry (LDV) is a non-contact vibration measurement technique using the Doppler effect. The LDV permits measurement of hot, miniature or soft surfaces, even under water, without mass-loading. Polytec vibrometers are eye-safe class 2 laser instruments use a low power Helium-Neon laser and can operate at distances of hundreds of meters.

Laser vibrometers are typically two-beam interferometric devices which detect the phase difference between an internal reference and the measurement beam. The measurement beam is focused on the the target and scattered back to the interferometer. The heterodyne principle used in Polytec vibrometers generates an FM carrier to provide the directional information, and also opens the possibility to digital traceable vibrometry.

Polytec's many years experience have brought about a range of special-applications laser vibrometers for use on rotating surfaces, at very high speeds (30 m/s) and at very high frequencies (30 MHz). Polytec vibrometers measure not only velocity, but also direct displacement.

 

Laser Basics

Vibrometry Basics

Signal Processing

Surface Effects

Measurements in Transparent Fluids