On Fri, 12 Oct 2007 13:19:59 -0700, The Phantom
wrote:

On Fri, 12 Oct 2007 11:24:17 -0700, John Larkin
wrote:

On Fri, 12 Oct 2007 01:55:12 +0100, "john jardine"
wrote:


"The Phantom" wrote in message
...
As promised.


[Useful reading. But yes, there's caveats with the 'x2' limit.]

Attached, a contrived, LTspice structure, giving 2 gain.


Cool. It did seem like cascading could be done without theoretical
limit. The voltage looks like it's increasing exponentially with stage
count.

I simulated it too. John has 3 orders of magnitude increase in impedance
level per stage. With only two orders increase, the gain was around 1.8
after 7 stages. With one order increase in impedance level per stage, the
gain was decreasing with each stage except for the last stage (which is
unloaded), where the gain does increase.


The within-stage parts ratios, currently 100:1, could also probably be
optimized for the cascade situation. A lower ratio might give a little
less boost per stage, but might make the cascading situation better,
so the stage-stage impedance ratios might come down.

Complex!

John