Sean Breheny wrote:
> For example, if we have a filter factor of 16, with Olin's example,
> and using integer math, we have:
>
> FILT<--FILT + (NEW-FILT)/16
>
> If the absolute value of the difference NEW-FILT is less than 16,
> nothing ever happens.

Right.  You generally want to use Log2 fraction bits to avoid this.

However, the other version doesn't give you a free lunch.  It looks like
TOTAL will float around the value times the same factor that you're dividin=
g
by in the equation above.  That just means you're adding the bits on the
left instead of the right.

So you have to leave overflow bits on the left or add the same number of
fraction bits on the right.


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