Hello Lee,
How do you know the resonance frequency? Depending on observation or your
design value? In my experience, the resonant frequency is the one at which
the amplitude is the biggest. So I think perhaps this lower frequency
is not the resonant one which you think should be.


Yahong


On Thu, 11 Feb 1999, Chua Bee Lee wrote:

> 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
>
>
>