As the second step random excitation will be performed. After the random another low level sine is done to verify that there was no change as compared to before. If a sine burst is possible, another low level sine can be performed thereafter. These provide 14 direct channels and a maximum of 2 times 14 channels on two tape recorders. The maximum number of channels is 38, constrained by the number of charge sensitive amplifiers available.
Sensors are piezoelectric probes without built-in electronics.
Sensors will be allocated such that their size and mass have the least possible impact on the measured results. To measure responses in all three directions tiny cubes for stand offs will be used. Responses at the above indicated positions will be recorded. Partly they will be directly accessible during the tests, the rest will be on the tape recorders. For easy comparison and cross calibration some TBD channels' signals will be evaluated on line as well as fed into the tape recorders.