[sdiy] RMS converter schematics

[Byron G. Jacquot]

>Hello,
>
>I'm on the lookout for some schems that will take an AC signal (or one that has been full wave rectified) and output a 'true' RMS signal.
>
>I have the Texas Instruments app note SNOA855 and a couple of versions of the DBX 160 RMS detector - but I was wondering if you lot could point me to or suggest any others.
>
>Interested in anything from cheap and cheerful to pro.

TAHT Semi had the 2252 RMS converter IC, now replaced by their "analog engine" family, like the 4301 or 4305.

There's also a schematic for one in the Sergio Franco book.  Page 620 in the edition on my shelf.  4 opamps and maybe 6 BJTs.  I've been meaning to play with it sometime.

-Byron Jacquot