Hi, zach, bloki, Optikon, Ron H,
Thank you Ron H, and if i understand you correctly, you describe converting
this wave-form into digital form, in order to use it in some way.
Well after some considerable thought, that is pretty much the same lines as
i was thinking.
For this purpose the shape of the Very Low Frequency wave is known, and yes
it could easily be sampled many times, and an average produced, which could
then be 'looped' as you describe.
This would produce a locally generated wave-shape, which could then be used
against the input from the sensor, which would be highly amplified.
I was thinking carefully about what i said about the centre-zero meter going
from side to side slowly.
Took me a while to realise i was thinking about BFO, then i realised that the
meter wouldn't really act like that, because the frequency difference wouldn't
show up unless it was rectified. Then it would show as slow forward surges.
That would probably be acceptable.
I feel that such an arrangement would have a very very high 'rejection' co-ef
or 'Q' as they used to call it. This application has to differentiate signal
from a lot of background vibrations.
I think that will do the job, i will start getting things together to make
this project.
Cheers, John