S&H

[Martin Czech]

> > The best sample and hold is an A to D convertor & a memory,
> > and then D to A.
> > Will wait for say, until the eventual heat death of the universe
> > with no droop. 
> > My challenge to the list: how cheap can you make this?
> > Perhaps with a PIC?
> 
> No PIC required.
> A counter, a comparator and a DAC should do.
> Start the counter when the sample pulse arrives, stop the counter when the
> comparator signals that input = output.
> 
You could even try a cheap two stage design:
cheap 8 bit dac (succesive approx.) then the same chip scaled
down  with resistor network, BUT trying to find the optimum in a 
linar fashion, ie. linear output increase. Takes additional 256
steps, but these can be very fast, since the comparator sees no
large voltage steps. Of course, one has to wait for settling down,
after each step (glitches).
But if you do all this, you coulr really use a adc/dac pair,
maybe with eprom between, this gives a qunatizer.

m.c.