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High Frequency Noise From STWINMA2A

xiaohangz
Associate

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.

xiaohangz_0-1704828877639.png

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.

xiaohangz_1-1704828956551.png

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

Thanks!

 

 

3 REPLIES 3
AScha.3
Chief III

Hi,

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 ? 

If you feel a post has answered your question, please click "Accept as Solution".

Hi

 

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.

 

Thanks.

Federica Bossi
ST Employee

Hi @xiaohangz ,

Did you solve?

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