Are Class D Amplifiers really "digital"?

[SoundAndMotion]

An intelligent, cogent argument can be made that Class D is analog.

 

An intelligent, cogent argument can be made that Class D is digital.

 

Professionally, we call this "a gray area". I assume the goal of this thread is for anyone interested to argue that this shade of gray is most definitely [black, white, both, neither]. Put me in the minuscule group who would argue "neither". I don't want to be the first to argue my point though, and I haven't looked for an authority (wiki, Paul, random youtube dude) to appeal to.

 

IMHO, discussion of what makes something "analog" or not could be intellectually stimulating and informative, and fits just fine in this sub-forum. Thread-crapping with armchair moderation seems OT to me. But I don't own the forum, nor am I a moderator.

 

I shouldn't need to point out that there are a couple of "Ignore" functions, so those who've set their hair on fire worrying that this topic is in the wrong place can protect their delicate eyes from the Medusan threat.

[SoundAndMotion]

5 hours ago, Miska said:

 

Since DSD is essentially PWM, 

 

That's not true, as the video @kumakumalinked below and many web pages explain. DSD is PDM, pulse density modulation, and the way it's encoded and decoded is different from PWM, pulse width modulation. In some ways they look similar, especially with full scale simple sine waves, but they're not the same.

This OT post of mine doesn't answer the "analog-ness" though.

On 9/12/2020 at 4:59 PM, kumakuma said:

 

 

https://www.psaudio.com/pauls-posts/dsd-and-class-d/

 

 

 

[SoundAndMotion]

Well, you sound like an engineer and I'm not, but I learned the distinction from engineering web sites, not Wikipedia. The difference between "similar" and "same" is semantic. Even the Wikipedia article you cite says:"For a 50% voltage with a resolution of 8-bits, a PWM waveform will turn on for 128 clock cycles and then off for the remaining 128 cycles. With PDM and the same clock rate the signal would alternate between on and off every other cycle. The average is 50% for both waveforms, but the PDM signal switches more often."

So the methods and ideas are related, but the implementation is different, i.e. the signals will be different, except at the peaks where they're the same. And several engineering/programming sites describe them as related, but different.

 

But you win.... to battle this out would be pedantic.