Finding Resonance of mass Idea!

Dave ( gravman@netinc.ca )
Sun, 25 Jan 1998 14:37:07 +0500

To All!

I've been monitoring the exchange of questions and answers on the
subject of finding the natural resonate frequency of objects, and not
once did I read a suggestion of using a "Laser Beam Listening Device"
and a Laser transmitter source which is modulateable!

By shining the first laser beam on the mass object modulated with a
multitude of test scan frequencies, and a second laser beam "listener"
device focused on another side of the same mass connected to a oscope
for amplitude monitoring, should this procedere not reveal excitement
frequency(s)?

Maybe a Laser Listener (receiver) that is commonly available can be
modified to provide an extended flat frequency bandwidth response output
capability, by modifying or bypassing the low pass audio filter circuit.

Would the background noise level be too high?

I think this method offers close to Zero loading or dampening on the
mass, which in turn should NOT give false readings.

Does anyone know how high of a frequency range that could be achieved?

Now, how do you suspend/support the mass under test? Rubber bands?

Any Yeh or Nay on this concept?

<Dave>