> >My problem is in understanding the function those components
> >in the diagram have from the PWM output to the op-amp.
> Specifically
> >what the relationship is between the PWM coming out from the
> PIC
> >and what is going on with the resistors and caps.
>=20
> That network of resistors and capacitors functions as a low-pass
> filter: it takes the high-frequency PWM signal and removes the
> AC
> components (or most of them, anyway, except for a little bit of
> ripple) from it, leaving only the DC component which represents
> the average value of the PWM waveform.
>=20
> Dave D.
>=20


I remember LPF's and HPF's from studying about synthesizers.  Like, for =
instance, passing a noise through it and getting a cymbal or drum sound.

But you mention DC components.  I don't understand that.  What does that =
have to do with the DC PWM signal?  Where was the AC in the mix?

And most importantly, why or what about the PWM signal made it necessary =
to low-pass-filter it?  What where they trying to get by it?

Thanks for helping a learner!

Lindy


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