Interface module enables MEMS microphone array testing

Audio Precision has introduced a PDM 16 module for the company’s APx500 Series audio analysers. The module offers simultaneous acquisition and measurement of up to 16 channels of pulse density modulation (PDM) signals, making it the highest channel-count solution available for MEMS microphone and MEMS mic array testing, claims the company.

PDM 16 is an optional interface module for the APx555, APx52x Series or APx58x Series audio analysers. The input module is installed in the analyser, and there is also a remote interface pod and an extension cable. The module provides sample-accurate inter-channel phase information, critical data for the creation of MEMS mic arrays. Developers of systems using beamforming microphone arrays and other DSP-based multi-channel audio acquisition applications depend on a true representation of phase alignment of the input channels to validate their algorithms and designs. PDM 16 uses synchronous sampling based on a common clock, for a clear picture of the phase relationship between channels.

An acoustically-silent remote pod and extension cable preserve PDM signal integrity for up to 10 meters, enabling the PDM 16 to support microphone measurements in anechoic chambers. The module can also provide up to 50mA Vdd power supply to the device, or devices, under test.

MEMS microphones are extremely small microphones that use a PDM stream for digital output. MEMS mics, either individually or in an array, are used in smartphones, hearing aids, mobile computing, automotive systems, smart speakers and other IoT systems.

As an APx module, PDM 16 is part of an integrated audio test solution, leveraging the combined power and flexibility of the APx500 audio measurement software and test hardware for signal generation and acquisition. Along with PDM 16, APx500 Series analysers can include modules for testing components or systems that also use interfaces ranging from analogue to chip-level I2S and TDM protocols, Bluetooth or HDMI. A PDM 16-equipped analyser can be equipped with the existing APx PDM module to add two channels of PDM output, as well as power supply rejection (PSR) and jitter measurements.

The APx PDM 16 module is available to order now.

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