



	Typical (in the old 2x-oversampling units) was a thirteen-tap
FIR, implemented as a dedicated hardware addition circuit.  At this kind
of speed (slow, by digital standards) such an adder is much less
expensive than analog components of comparable precision.

	I gleaned this information from a hardware manual for
an old CD player design; where one would find similar info for
a particular CD (the digital filter IS an interesting component,
from my point of view), I have no idea.  The digital filter
is a kind of interpolation scheme (read a book on numerical 
analysis, to see just how BROAD the term 'interpolation' is...),
