[sdiy] jitter analysis

[Czech Martin]

> >We do not have to argue about the real limitation of the human ear.
> >At some frequency all perception will be lost. My ears can go as far
> >as 16-17 kHz, others may reach 22kHz. But not much more.
> 
> That's for steady tones though. The perception of transients 
> is much more 
> complicated.
> 

As long as we model the ear as filter bank or DFT, I can not follow
this argument. I can model any transient as repetitive wave train
with a fourier series composition. If I chose 1 hour repetition time,
it doesn't appear repetitive. Then all the linear stuff applies
as well, for example band width limiting.
A transient has a very broad spectrum, an ideal pulse is "white"
in some way. So you can not say that a transient has this or 
the other frequency, but the spectrum is really broad in long time
Fourier transform, or sharper and decaying in hopping short
time transforms.

So it is quite natural that a band limited system like the ear
can still hear transients with their mean short time DFT components
out of band, because there is still enough "leakage" into the
pass band. 

Of course, this model is very crude and not sufficient.
OTOH it is simple enough to be usefull.

The other observation of broadening spectra via noise is very good!


m.c.