Dear All,
        I have been working on folded beams resonators using square waves
to drive them. As I adjusted the driving frequency towards the resonance
value, I observed resonance at smaller amplitudes  at lower frequencies
prior to the one that I was expecting. I would appreciate if someone can
provide some insight on that.

        Thank you.
        CHUA Bee Lee
        Department of Mechanical and Production Engineering
        National University of Singapore