What is PDM format?

[Vyacheslav Azarov]

Posted on March 17, 2017 at 17:25

Hello,

I want to use MP34DT01 microphone in our application. But data stream format is unclear. Explain this please. I guess this is the usual delta modulation. Is not it? Analog Devices for ADMP521 was describe it transparently.

Thanks in advance.#pdm #microphone #mems-microphone

[Farhan Khan]

Posted on April 21, 2017 at 13:46

A form of modulation using which an Analog signal is represented by a Binary signal.

If you are familiar with PCM where magnitude is used to represent Analog signal, in case of PDM relative density is used

Go through the links

http://keystrokecountdown.com/articles/PDMPlayground/index.html

https://www.theunterminatedstring.com/probing-pdm/

http://renesasrulz.com/renesas_forum_home/rl78/f/the-rl78-forum/5890/mems-microphone-pdm-decoding

Regards

Farhan

[Vyacheslav Azarov]

Posted on July 23, 2017 at 06:12

Thank you Farhan for references. As I was understand MP34DT01 is functional equivalent of ADMP521, is not it?

[Farhan Khan]

Posted on March 30, 2018 at 08:40

Yes. Both IC's provide output in PDM format and MP34DT01 can be used to replace ADMP521.