Is it possible to get 32bit data from PDM to PCM l... - STMicroelectronics Community

Hi all,

We are using stm32 PDM to PCM library to convert PDM mic data into PCM data. On that we had an option to control the mic gain from -12db to 51db as mentioned in data sheet.So we try to increase the db level, But we cannot able to increase the db level more than 11db. If we increase the db level more than 11db the converted PCM values goes more than 32768(as signed).But the PDM to PCM library returns only 16bit data.

Is it possible to get 32bit data from PDM to PCM library?

Otherwise is there any other solution to solve this problem?

I would be glad if anyone has some advice for me.

Thanks in advance.

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3 REPLIES 3

How about using CMSIS DSP?

https://www.keil.com/pack/doc/CMSIS/DSP/html/group__FIR__decimate.html

Thanks @victagayun

But we didn't use any CMSIS DSP now. We just use PDM to PCM library provided by STM.In the user manual mentioned as algorithm was implemented with 16bit resolution.Is there any other solutions to do get 32bit data from that library.

I had some problem with PDM filter https://community.st.com/s/question/0D53W000019CZzmSAG/pdmfilter-erroneous-1st-2-pcmconverted-data, maybe you know something about it.

Anyway, you can try the CMSIS and let me know the result.