Through-Zero FM

[WeAreAs1 at aol.com]

Hello DIY listmates,

I have read the term "through-zero FM" several times, in previous posts found
here.  Usually with the writer referring to it in glowing terms lavish with
praise.  I, too, now wish to wallow 'n' revel in the wholesome goodness of
through-zero FM.   So, could someone please be so kind to explain the concept
to me?  (and to the rest of the list, of course!)  Also, what are some musical
applications and sonic characteristics of through-zero FM?

Very best regards,
Michael Bacich