> I see occasionally in tv sets and the like aluminum (?) shields or
> screens covering a particularly sensitive (or radiating!) sections of
> circuitry.  My question is ... are these available anywhere?  Or are
> they typically something that is made in a metal shop along with
> whatever chassy metalwork that needs to be done?
>
> If I have them made, is any particular types of metal better or worse
> than others?  Right now I'm thinking of just a vertically mounted
> "strip" or "wall", kind of like a tennis net, say, between the two board
> sections.

Using a "can" is the last resort.  Sometimes it's the only answer, but
good layout can go a long way.  The single most important piece is a good
ground plane, not only on the sensitive circuit, but also on the radiating
circuit.  Of course the two ground planes need to be separate with only a
single connection point in such a place where the only current will be the
power supply return from the analog section.  The power supply to the
analog section should be separately filtered.  A preamp shouldn't draw
much current nor need large voltage swings, so this can be as simple as
one or two R/C in each supply line, located physically straddling the gap
between the two ground planes.  The next thing would be to keep the high
impedence and high sensitivity signals as short and far away from the
noisy circuitry as possible.  Ideally each high sensitivity input has its
own shielded cable which attaches to the board right at the preamp input.
If you do all this, you probably don't need a can.

As to where to get cans and fences, I don't know since I've never tried.


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