Go Down

Topic: PWM dithering explanation (Read 3342 times) previous topic - next topic

RobvdVeer

During my implementation of software PWM for my project (hardware pwm no option), i stumbled on an interesting algorithm. I have tried to write an explanation on my blog here: http://simplicate.weebly.com/1/post/2013/05/using-bresenham-line-algorithm-for-better-pwm.html

I hope you find it useful. Thank you for your time!
Rob
Follow my progress on http://simplicate.weebly.com

Chagrin

Great minds, etc.

http://forum.arduino.cc/index.php?topic=149369.msg1121850#msg1121850

RobvdVeer

Haha indeed! Had i known this, etc. etc.

One of those moments where google failed.
Rob
Follow my progress on http://simplicate.weebly.com

stimmer

This is called Pulse Density Modulation (PDM) since it is no longer the exact pulse width but the average density of the pulses which conveys the analog value.
Due VGA library - http://arduino.cc/forum/index.php/topic,150517.0.html

Headroom

#4
May 21, 2013, 03:30 am Last Edit: May 21, 2013, 03:33 am by Headroom Reason: 1
Very interesting. Never thought of that.

Little correction on the article. The flicker frequency " for lack of better words" of 30 is too low. For a TV that's ok as usually pixels are not turned from full on to full off etc.
However PWM dimming does just that so the min frequency that will not be noticed by most people is 100Hz.
http://trippylighting.com

http://ledshield.wordpress.com/

RobvdVeer


This is called Pulse Density Modulation (PDM) since it is no longer the exact pulse width but the average density of the pulses which conveys the analog value.

I guessed there was a proper name for it. Thanks.

The flicker frequency " for lack of better words" of 30 is too low. For a TV that's ok as usually pixels are not turned from full on to full off etc.
However PWM dimming does just that so the min frequency that will not be noticed by most people is 100Hz.

Also noted. I'll correct the text!

Thank you both. It's not easy to be correct with so many prying eyes on the web, lol  :)
Rob
Follow my progress on http://simplicate.weebly.com

Go Up