Sun Aug 14 15:36:40 CEST 2011
Back to the sawtooth example. It's a nice one because it has:
- different data types (int, float)
- time dependency
The mix of time-dependency and nonlinearity means that the only simple
representation (I can think of) is as a state-space model.
Actually, the int is not really an int, it's used as a phasor (angle).
\ (th, x2, freq) -> (th', x2', out) where
th' = th + freq -- update phasor
x = ph2i th -- convert phasor to [0,1[
x2' = x * x -- square
out = x2 - x2' -- filter (differentiate)
( very wrong, but the idea seems ok. )