AN3998 PDM Audio Software Decoding on STM32 Microcontrollers Application Note

It introduces how to connect STM32 with MP45DT02 MEMS Microphone and use PDM signal decoding and audio signal reconstruction to convert PDM data to 16-bit pulse-code modulation (PCM) format

Brand: STMicroelectronics
Category: microcontrollers
Document type: Application Note
Language: English
Pages: 10
File format: PDF
File size: 91 KB
Published: 06 August, 2012
Updated: 30 September, 2023
Model: STM32
MD5 checksum: 6015FB4811B5B77CDCC2A6B86F85C9B9
PDF: AN3998 PDM Audio Software Decoding on STM32 Microcontrollers Application Note PDF

About this manual

The document presents optimized software implementation details for converting Pulse Density Modulated (PDM) data from an ST MP45DT02 MEMS microphone into 16-bit pulse-code modulation (PCM) format. It covers the necessary hardware interface setup and digital signal processing algorithms, including decimation filtering and conditioning.

What's inside

Introduction
PDM signal introduction
Hardware interface: microphone connection and acquisition
Software interface: digital signal processing
PDM audio software decoding library description

Frequently asked questions

What frequency range does the PDM signal from the MP45DT02 MEMS microphone cover?

The microphone outputs a high frequency stream of 1-bit digital samples ranging from 1 to 3.25 MHz.

How is the microphone gain controlled in the software?

Gain can be controlled by an external integer variable (MicGain) using the equation G = MicGain/64.

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