21 Sep
2008
21 Sep
'08
4:02 p.m.
On Sun, Sep 21, 2008 at 8:56 AM, Claude Heiland-Allen claudiusmaximus@goto10.org wrote:
Damian Stewart wrote:
Charles Henry wrote:
There is no zero at z=0. I'm not sure about this one--but it seems as though it's impossible to have a zero at z=0?
a zero at z=0 is a delay of 1 sample, so in:
y = a x(0) + b x(-1) + c x(-2) + d y(-1) + e y(-2)
there is a zero at z=0 if a == 0, and two zeros at z=0 if a == 0 and b == 0
(iirc)
z^-1 is the unit delay operator.... so, Y(z)=z*X(z) means y(n) = x(n+1)
while this is not impossible... it's non-causal. For real-time filtering, you can't already know the sample that comes next. I've been thinking about it for a little while now. I hope we can figure it out
Chuck