Total Harmonic Distortion (THD) is a measurement of how accurately a vibration system is reproducing the output signal from a controller. The VR9500 can be used to measure the THD during a sine sweep and validate the accuracy of a shaker system.
THD can be useful in maintenance programs when tracking system changes over time. It can also compare different fixture responses as well as product design.
Most systems will include an amplifier distortion rating, but not a shaker distortion rating. THD can be used as another way to compare multiple systems as THD is a cumulative value for the amplifier, shaker, and accelerometer system as a whole. In a perfect system, the THD would be zero. Most systems will be well below 10% across the operating frequency. The system resonance can be significantly higher, even above 10%.
Use Vibration Research’s THD tools to measure the distortion in your system today!