A delta function can be built from a linear combination of periodic signals, and it is definitely a signal 'with onset'.
Or, In the same spirit, an onset can be periodically-extended by repeating it infinitely into the past and the future, and then it can be represented as a sum of countable (possibly infinite) number of periodic components.
On Thu, Oct 7, 2010 at 12:49 PM, Laszlo Toth
<tothl@xxxxxxxxxxxxxxx> wrote:
On Thu, 7 Oct 2010, Parncutt, Richard (richard.parncutt@xxxxxxxxxxx) wrote:
> So evolutionary-ecological theory predicts phase
> sensitivity in the onset, and insensitivity after that.
Sorry for using your comment for this purpose, but I would like to point
on yet another source of confusion with the term "phase". Mathematically,
only periodic signals can have a phase, so anything that has an onset is
excluded. In this case you are talking about "delay" or "time shift".
Tha main diference is that phase shift is limited by the period length of
the periodic signal, while time shift can be of any size.
(If I were a mathematician, I'd say that, as a periodic signal must be
infinite, no such signal can exist in real life...)
Laszlo Toth
Hungarian Academy of Sciences *
Research Group on Artificial Intelligence * "Failure only begins
e-mail: tothl@xxxxxxxxxxxxxxx * when you stop trying"
http://www.inf.u-szeged.hu/~tothl *