Correct Excitement

For a correct excitation, the following must be ensured:

1. Excite the frequency range of interest with a high amplitude which is above the background noise of the sensor.
2. Examine an amplitude uniformly distributed over the frequency range.
3. Enough energy must be generated to excite the entire frequency range of interest, but not significantly beyond that.
    
4. The force must not drop more than 20 dB in the excited frequency range to obtain sufficient energy input.
5. Sufficient force should be induced into the structure to excite the structures' modes.

A course over the frequency range to be examined with a correct excitation is shown in Fig.1: