26. September 2019

Quality Testing digital MEMS Microphones

With the expanding use of voice control, digital MEMS microphones are finding their way into more and more devices in the areas of communications, entertainment, mobility, medicine, and the home. As a rule, several MEMS microphones are installed as an array in each device in order to facilitate features such as direction-selective hearing and noise suppression. With the NTi Audio Microphone Test System, the quality of each of the digital MEMS microphones as well as that of the microphone array as a whole can be quickly and reliably measured.

At the core of the Microphone Test System is the FX100 Audio Analyzer. This connects to the digital MEMS microphones through the NTi Audio MEMS Mic Interface Box. Up to 8 digital MEMS microphones can be assessed with configurable clock frequencies and operating voltages. A reference loudspeaker and measuring microphone ensure accurate and reproducible acoustic test signals.

Block diagram: Test system for digital MEMS Microphones

The NTi Audio RT-Mic PC Software coordinates all measuring processes, visualizes the results and assesses them against good/bad criteria. The typical parameters for a test are sensitivity, frequency response, distortion, and signal-to-noise ratio (SNR). The results from the entire microphone module, as well as the deviations of the individual microphones are relevant.

Measurement Results from an assembly with six digital MEMS Microphones