El Mon, Dec 29, 2003 at 10:40:57AM -0600, Martin McCormick escribio:
>         I was thinking of building a PIC-based audio amplifier with AGC.
>
[...]
>
>         Then, I read something in an article that made me think a bit
> more.
>
>         The article lead me to think that one must have a DC carrier
> on the audio signal across the pot which means that the wiper will
> step a DC voltage up and down along with the audio.

IIRC, you only need to connect the Vb pin to a lower voltage than the
lowest analog input. Analog voltages can go from Vb to Vcc.


> The trouble with
> that is you can probably hear that as a series of clicks or a buzz as
> the pot "turns."  If the circuit needs to go from pot full up to
> almost all the way down, you might hear a substantial pop.  This would
> not be acceptable as your audio would always be full of extra noise.

This will not be the case if you connect it correctly:

  In   --,
         <
         <<--- Out
         <
  Voff --'

Voff is the offset voltage.

    Daniel.

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