Graeme Zimmer wrote:

> Switched capacitor filters are analogous to conventional multi oppamp
> filters such as Biquad or State Variable.

  Ah yes!  Now I recall.  A bit vague of me.

  I recall when a local magazine published a telephone modem using
switched capacitor filters, quite a while ago.  Had a bit of a bad
reputation which I take to indicate the difficulty of taming such a
beast implemented in discrete components with switching frequencies
floating about...

  In a single IC; a much better proposition.
--
  Cheers,
        Paul B.