Frequently Asked Questions about Laser Doppler Vibrometer

Laser Doppler Vibrometer exhibit varying levels of sensitivity (coherence) depending on the distance from the sensor end face (× lens end face), due to the configuration of the laser tube and interferometric optics used. Measuring at a distance with high sensitivity allows for measurements with a good signal-to-noise ratio (i.e., sensitivity adjustment is easier).

*The distance here refers to the distance from the tip of the lens to the object being measured.

• Sensitivity is best at 170 mm from the sensor edge (lens edge), and then improves every 200 mm thereafter. Conversely, sensitivity decreases around 250 mm and every 200 mm thereafter after 450 mm.
• When using extension rings: With the LV-1300 and LV-1600 series (older models), the above distances will not change even if you use or change the "extension rings" used to vary the measurement range.

In the LV-1700 series, the focal position where sensitivity is maximized is indicated by a "○ mark" on the sensor, as shown in the diagram below.