The Laser Doppler Vibrometer has high and low sensitivities (coherence), depending on the configuration of operating laser tube or the interference engineering system, and according to the distance from the sensor edge (edge of the x lens). The measurement which is good in the s/n ratio can be operated in the high sensitivity distance measurement (=easy to adjust the sensitivity).

 

* "Distance" in this graph is the distance from the tip of the sensor to the measurement object.

 

• The sensitivity is high when the distance from the sensor edge (tip of the lens) to the measurement object is 170 mm and after every 200 mm. The sensitivity falls into low when the distance is 250 mm, 450 mm and after every 200 mm.

• When close-up ring is used: The above distances won’t change when "close-up ring" which is for the adjustment of the measurement range for the previous models of the LV-1300 (discontinued) and LV-1600 (discontinued) is used or replaced.

 

 

For the LV-1700 series, the "○ mark" of the sensor in the following figure shows the focal position of the maximum sensitivity.