Re: OT: Cap and Trade

On Jul 24, 12:06 am, John Larkin
<jjlar...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
On Wed, 22 Jul 2009 20:09:36 -0700 (PDT),Bill Sloman

<bill.slo...@xxxxxxxx> wrote:

I hate bang-bang controllers, and I've yet to have to come to grips
with the detailed design of delta-modulation ADC's.

Switching regs are bang-bang controllers.

But mostly they are designed with enough output filtering that the
switching noise doesn't get out to mess up the world outside. My
intermittently cited Peltier junction paper

"A microcontroller-based driver to stabilize the temperature of an
optical stage to within 1 mK in the range , using a Peltier heat pump
and a thermistor sensor"
A W Sloman, Paul Buggs, James Molloy and Douglas Stewart 1996 Meas.
Sci. Technol. 7 1653-1664

includes a deterministic scheme for reducing the lower frequency hard-
to-filter components of the switching noise, and a tolerably fancy
filter to deliver a tolerably steady current to the Peltier junction.

A d-s ADC is a simple bang-bang feedback loop.

With a fancy filter to confine the noise inside the feedback loop.

The duty cycle of the
feedback - a 1-bit stream - is digitally filtered to produce the final
numbers. The banging in a simple integrator-feeedback loop tends to be
noisy, but higher-order loops can push the noise spectrum up (make the
loop more chaotic) and reduce net noise in the delivered data.

See above. I've long known about this in a general way,but have yet to
spend the time I'd need to be able to exploit it for myself.

I've long been a fan of chaotic processes, Mandelbrots, chaotic
control loops, attractors, fractals, and the weird and beautiful
patterns that can emerge from very simple systems.

And yet you think that all chaotic systems are impossible to predict;
you may be a fan, but scarcely a well-informed fan. Your ill-informed
comments on biology and economics.reflect a similarly unsophisticated
appreciation.

--
Bill Sloman, Nijmegen

.

Relevant Pages

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  • Re: OT: Cap and Trade
    ... switching noise doesn't get out to mess up the world outside. ... With a fancy filter to confine the noise inside the feedback loop. ... predicting future system states becomes impossible as the time horizon ...
    (sci.electronics.design)
  • Re: PLL convergence problem
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    ... > of inverters square and sine can cause problems with noise. ... Noise can come from many different sources within the inverter. ... > Inverter may actually have an intermediate inverter switching at 100kHz ... Can set the filter to just above 60Hz and should do nice ...
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