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

Posted on February 21, 2017 at 08:01

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?

regards 

vinod