
Home  Forums  Rules  Articles  diyAudio Store  Gallery  Wiki  Blogs  Register  Donations  FAQ  Calendar  Search  Today's Posts  Mark Forums Read  Search 
Class D Switching Power Amplifiers and Power D/A conversion 

Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving 

Thread Tools  Search this Thread 
1st July 2011, 12:45 PM  #1 
diyAudio Member
Join Date: Apr 2010

UPWM
I have read that NPWM(natural analog PWM) is fundamentally linear whereas UPWM(digital PWM) distorts the input signal. Intuitively, are not the pulse widths linear to the input amplitude in both the above cases?
Could someone please give me intuition on this or can point me to some resource which gives intuition on this. I have referred Karsten Nielson's thesis too, but could get only a mathematical proof. 
2nd July 2011, 12:13 PM  #2  
diyAudio Member
Join Date: May 2004
Location: Budapest

Quote:
Basically both methods generates some problematic spectral components, but while UPWM generates harmonic distortion, NPWM generates nonharmonic components. I can't tell why. PS: NPWM is not neccessarily analog and UPWM is not neccessarily digital. Both can be realised in both way, but the basic operation in theory is always analog! True digital "PWM" is a totally different thing (sigmadelta converters). 

2nd July 2011, 01:18 PM  #3 
diyAudio Member
Join Date: Apr 2010

pafi, thanks for replying. I have referred many papers. Everywhere, people tell UPWM is nonlinear and come up with techniques to approach NPWM. But they never explain intuitively why UPWM is nonlinear and why NPWM is linear.
Another doubt I have is that, even though the comparator is such a nonlinear block, the NPWM output spectrum is totally linear for the signal in the baseband. Can anyone please discuss their angle of viewing this property of the PWM. Last edited by terminator12; 2nd July 2011 at 01:23 PM. 
Thread Tools  Search this Thread 


New To Site?  Need Help? 