[From Rick Marken (960116.0801)]
[ The last version of this had some syntax errors; I hope this is
a tad more coherent]
Rick:
o := o + (k.2i-o)
Bruce:
But doesn't this reduce to just
o := k.2i ?
Rick:
Mathematically, yes. But with the replacement operation I think we just end
up adding an increment, k.2i-o, to o.
Bill Powers (960116.0500 MST) --
No matter how you think about it, o + k.2i - o is just k2.i.
You've left out the slowing factor,
Oops. So my simulation is a proportional rather than an integral system. As I
said in the part of the post that you didn't scan because of your compiler
policy, I think in way over my head (obviously, since I didn't notice that
o + k.2i - o = k2.i).
I think the relevant points in this discussion are:
1. X(n) = g X(n-k) does not describe a closed loop system and
2. When loop gain in a positive feedback system is >= 1.0 the system becomes
unstable.
Do these statements make it through the first pass?
Best
Rick