I want to do experimentation for different base acceleration amplitudes (a = 0.3g, 0.5g, 0.7g, 1g) like attached in this image.

The problem facing in this experimentation is

Using a function generator, we have two inputs i.e frequency and voltage amplitude.

Changing frequency and voltage amplitude leads to a change in the applied base acceleration.

I am following this procedure (Right or wrong I don't know)

Because of requirement of constant base acceleration for the particular frequency range, i need to maintain the voltage amplitude correctly for different frequency values to get constant base acceleration amplitude.

Tell me your suggestions regarding this.