<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""><div><br class=""></div></div><div><blockquote type="cite" class=""><div class="">On 5 Nov 2022, at 11:40, Mike Bryant <<a href="mailto:mbryant@futurehorizons.com" class="">mbryant@futurehorizons.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">I'll second using PDM, which I've used since the 1980s on all sorts of products. not just synths. Better results from DC up to high audio frequencies. <span class="Apple-converted-space"> </span><br class=""></div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;"><br class=""></div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">The easiest way to get PDM is just to reverse the bits from the PWM counter to the PWM comparator, but not all MCUs support this mode.</div></div></blockquote><div><br class=""></div>Oooh, that's clever! I'd never seen that before. That should *absolutely* be a hardware feature on every chip with PWM. Dead simple to do at the silicon level, and offers a big improvement over not doing it.</div><div><br class=""></div><div>The way I know is using an NCO set to output a single pulse when it overflows. Using increment values up to the full maximum value of the accumulator gives you "overflow pulses" that are output more frequently with larger increments - PDM.</div><div><br class=""></div><div><br class=""></div></body></html>