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how can i use delay and sum beamforming algorithm between two microphone  pcm data?

Question asked by Jaiswal.vinod on Feb 22, 2017
Hi all,


1. I have two question before developing my delay and sum beamforming algorithm.

A). I am working on Stm32 STM32F401RE NUCLEO with X-NUCLEO-CCA02M1 on Stm32 OsxAcosticBF stack in this source code they are collecting microphone PDM data in to this" I2S_InternalBuffer"

''uint16_t * DataTempI2S = &(I2S_InternalBuffer[X_NUCLEO_CCA02M1_Handler.PdmBufferSize/2]);
uint8_t a,b=0;
for(index=0; index<X_NUCLEO_CCA02M1_Handler.PdmBufferSize/2; index++) {
a = ((uint8_t *)(DataTempI2S))[(index*2)];
b = ((uint8_t *)(DataTempI2S))[(index*2)+1];
((uint8_t *)(X_NUCLEO_CCA02M1_Handler.PDM_Data))[(index*2)] = Channel_Demux[a & CHANNEL_DEMUX_MASK] | Channel_Demux[b & CHANNEL_DEMUX_MASK] << 4;;
((uint8_t *)(X_NUCLEO_CCA02M1_Handler.PDM_Data))[(index*2)+1] = Channel_Demux[(a>>1) & CHANNEL_DEMUX_MASK] |Channel_Demux[(b>>1) & CHANNEL_DEMUX_MASK] << 4;''


 after demuxing R/L data they are passed that data into PDM library which is  convert  R/L data(PDM format ) into PCM format.

here i want to know- that  PCM data they are collecting into any buffer or directly  they are passed into OsxAcosticBF algorithm library .


B.) how can i use delay between two microphone after getting PCM data because that data in digital format?