8:1 Microphone Aggregation

Data aggregation and bridging between devices supporting various protocols in audio space

Pulse density modulation (PDM) is a popular way to deliver audio from microphones to the signal or application processors inside mobile and IoT devices. PDM is ideally suited for this task because it brings the benefits of digital, such as low noise and freedom from interfering signals, at low cost.

For signal processors that do not have enough PDM inputs or only have an I2S interface, the iCE40 UltraPlus microphone aggregation reference design allows the connection of up to 8 microphones to a processor over I2S bus.

Multiple microphone are becoming widely used in personal assistance devices for audio beamforming. A microphone array is used to form a spatial filter, which can extract a signal from a specific direction and reduce the contamination of signals from other directions.

Features

  • Aggregate 8 PDM microphones and connection to a processor over I2S
  • Support beamforming capability by using multiple microphones
  • Use any 48KHz PDM microphone
  • Excellent system function response that does not affect audio quality
    • THD Level = -112.336dBFS
    • Noise Level = -96.102dBFS
    • THD+N Level = -96.008dBFS

Block Diagram

Documentation

Quick Reference
Downloads
TITLE NUMBER VERSION DATE FORMAT SIZE
iCE40 UltraPlus 8:1 Mic Aggregation Demo User Guide
FPGA-UG-02035 1.1 1/18/2018 PDF 1.5 MB
TITLE NUMBER VERSION DATE FORMAT SIZE
iCE40 UltraPlus 8 to 1 Microphone Aggregation Design Files
1.0 1/2/2018 ZIP 47.7 KB