PSN-L Email List Message

Subject: Re: detector design
From: Ron Thompson rlthompson@.................
Date: Sat, 08 Sep 2001 16:33:30 -0230


    This helps

"Charles R. Patton" wrote:

> This approach sounds fine.  One variation that might be interesting is
> to mount the radiating panel on the boom, but make that panel out of
> double sided PC board.  Drive it with a center-tapped RF transformer.
> That way your 180 degree phase is on opposite sides of that panel and
> you can resonate the capacitance of the panel easily, which makes
> driving it easy.  Now the pick-up plates will be stationary and close to
> the detector circuit and easily shielded with short lead lengths and you
> can null their output with simple summing which is then fed to a
> synchronous detector (an RF mixer) in order to recover the direction of
> displacement.

    A quick question at this point.  I had thought about driving the two
stationary plates using the centre tapped transformer and have the receiving
plate move as there would only be a single detector instead of two that would
need to stable and matched with respect to each other.  But perhaps this
isn't a problem if the two receiving plates feed the two opposite ends of
another centre tapped transformer.  This transformer would have two identical
coils wound in opposite directions and the centre tap connected to the
receiver/detector.  With the radiator centred the two receiver plates would
have identical voltage and opposite phase and the two oppositely wound coils
on the detector would cancel each other.  Through in a couple of variable
resistors, or whatever to balance the detector circuit initially and it
should stay balanced.  Comments?



Public Seismic Network Mailing List (PSN-L)

[ Top ] [ Back ] [ Home Page ]

Larry Cochrane <cochrane@..............>