Using ADAU1761 for microphone beamforming

Document created by BrettG on Oct 9, 2012
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We used an ADAU1761 to create a simple microphone beamforming application, with two omnidirectional ADMP504 MEMS microphones mounted in an endfire configuration.


Using the attached Excel sheet to perform the calculations, we calculated that a total of 6 samples of delay are required to generate a delay appropriate for a microphone spacing of 42 mm at a sample rate of 48 kHz.


Distance between microphones (mm)42
Speed of sound (mm per sample @ 48 kHz)7
Samples to cover microphone distance @ 48 kHz6


The following project was created to realize the signal flow.


2012.10.09 11.23.53.jpg

Reference materials:

Microphone Beamforming Application Note

ADMP504 MEMS Microphone Datasheet

ADAU1761 Datasheet