Gene Fuller wrote:
I suppose you already are well aware of what AN 95-1
says.

Yes, nowhere can I find where a black box is required
for the purpose of hiding part of the system from the
observer.

When a concept is used to alleviate ignorance, it is good.
When a concept is used to promote ignorance, it is bad.
What you are trying to do is pretty obvious.
--
73, Cecil http://www.w5dxp.com