PDM vs PWM and stm32f103

[Meri96]

Hello everyone, although I researched, I could not understand the difference between PDM (pulse densty modulation) and PWM (pulse width modulation) in practice.
PDM: The analog modulation type in which the carrier signal pulse width changes according to the modulation signal. There is no change in the amplitude or position of the pulses. definition is made.

https://ars.els-cdn.com/content/image/3-s2.0-B0122274105001654-gr7.gif

PWM: a special case of PDM where the switching frequency is constant and all pulses corresponding to a sample are adjacent in the digital signal. definition is made.

https://circuitglobe.com/wp-content/uploads/2019/08/PWM-signal.jpg

It is described as the same in most sources, I can not see any difference in the graphics. Not used in fixed frequency in PDM? As an advantage, PDM allows ZVS / ZCS, reduces EMI, ok but how does it do it, what is the difference in implementation?

I have the stm32f103 microcontroller, can I produce PDM with this microcontroller?

 

[FvM]

PDM: The analog modulation type in which the carrier signal pulse width changes according to the modulation signal.

The definition is valid for PWM but not PDM although the pulse patterns may look similar in a shallow analysis. PDM is generated by switching a pulse of fixed length and frequency on and off. Sigma-delta modulator is a popular method to generate PDM.

 

[danadakk]

This might help. Principals the same but reference processor different.

http://www.cypress.com/file/90081/download

http://www2.ece.rochester.edu/~parihar/papers/delsig.pdf

Regards, Dana.