A unique sensing element construction optimizes the capabilities of this sensor. The result is a device which yields simultaneous dynamic acceleration and force measurements from exactly the same location on a test structure. Internal crystal isolation and tuned channel phase matching allows for the acquisition of Driving Point (DP) data with optimal spatial and temporal coincidence. During modal test studies, the importance of DP data is paramount since any error effects the scaled mode shapes directly. The required impedance transfer function can now be easily and accurately derived from the measurements made by this unique impedance head sensor.
The Type 8770A..., by construction, has negligible strain sensitivity which allows measurements on extremely flexible structures. Both acceleration and force sensitivities are unaffected by mounting torque or mass loading. The built-in high sensitivity, low noise and high stiffness features minimize force input requirements while still achieving accurate results. In many situations this is ideal since imposed stresses can be minimized and test fatigue can be ignored.