Ground Bounce?

Bradley L. Mendenhall (blm@bbt.com)
Mon, 4 Mar 1996 09:42:14 -0500

Any scope experts out there?

I am getting some wierd scope readings and would like some insight into what
the scope is telling me. I have an ungrounded eqipment shelf with a scope
probe connected to a ground pin. The local probe ground wire is connected to
the same ground pin. The scope is isolated from AC ground and is grounded to
the shelf's logic ground. The shelf has three solid ground planes in the
backplane. When I plug a board into the shelf, I get lots of noise and
oscillations showing up on the scope, reading up to +/-0.5 volts. Most
oscillations are in the range of 20 to 100 kHz.

Can anybody tell me what I am measuring here? Is this ground bounce? What
can I do to accurately look at the ground plane while plugging in a board?

Thanks for any help,

Brad

------------------------------------------------------------------------------
Brad Mendenhall blm@bbt.com
BroadBand Technologies, Inc. Phone: (919)405-4682
4024 Stirrup Creek Drive FAX: (919)544-5356
Research Triangle Park, NC 27709-3737