[sdiy] why 10V

[jhaible]

> The systems theory is based on the assumption that all processing
> elements are linear. I.e. that  f(c*x,t) = c*f(x,t). That is never the
> case in practice.
>
> Say if you have your cascade of N allpasses, and even when the output
> should stay within the output range of your opamp with an applied
> signal, that doesn't say anything about the outputs of the opamps 1 to
N-1.

Of course there is nothing such as a perfectly linear system. Make
that an "almost linear" system, or, more precisely, don't let any opamp
in the chain get near its clippling levels. Like this (actually the same
as my initial question, just the other way round):

We have a chain of N unity-gain, single-pole all pass filters.
We want to prevent the output of _any_ amp in the chain from
going above +10V or below -10V. What's the maximum input
level (Vpp) for this chain?

Really the same question as before; I just want to avoid a general
"everything in real life is nonliear" discussion. Could be interesting
as well, as a separate thread. Certainly related to the slew rate / BW
thread, and the recent servo loop discussion. But my question _here_
is another one. Linear case, increase of pp voltage swing by repeated
all pass filtering.

JH.