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High Frequency Noise From STWINMA2A


Hello everyone,

I am currently working with STWIN+STWINMA2A microphone array for ultrasonic signal processing. I use the firmware "AMicArray_Microphones_Streaming" and connect the board directly to my laptop as an USB microphone.

However, the data suffers from significant noise with certain frequencies.

I used Audacity to sample the data in an quiet environment, with the configuration as figure 1. The sampling rate is 96kHz.


The DFT of 10,000 data points is shown in the next figure, we can see a very high noise level at around 40k, 24k, and 8kHz.


Is there any thing I can do to fix this problem?






STWINMA2 is analog mic array - why an array , not just one mic ?


Is analog out - whats the preamp ? and the ADC ? any spec about noise and SFDR ?


Did you look at the signal at the adc input with a scope ? 

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With an array, I will be able to estimate the direction of signal arrival. Also, STWINMA2 is able to perform beamforming for ultrasonic signals less than 40kHz.


About preamp and other specs, I have not divided into them. You are right I need to check those carefully also look at the signal with a scope.


I will attempt to replace the cable and move away form my lab tomorrow. There might be high frequency electromagnetic ghosts in my lab.



Federica Bossi
ST Employee

Hi @xiaohangz ,

Did you solve?

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