Olin Lathrop wrote:
> N. T. wrote:
> > - hardware 10 bit PWM: change duty cycle from 500 to 501 is 0.2%
> > change.
> > - software 10 bit PWM: difference between "500 off / 500 on" mode to
> > "500 off / 501 on"
>=20
> But that changes the PWM period. If you change the PWM period as you chan=
ge
> the desired duty cycle, you end up with low frequency components in the
> signal. That can be fine in some cases, but it's not really apples to
> apples comparison.

If the hardware PWM doesn't give you the resolution you need, couldn't you
use delta-sigma techniques to keep track of the accumulated error, and
adjust the width of future pulses based on that? Perhaps a bit of dithering
(pseudorandom noise) could be added to help hide any spurious tones generat=
ed
thereby.

-- Dave Tweed
--=20
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