Author Topic: Receiving ultrasonic transducer picking up EM noise  (Read 504 times)

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Offline raff5184Topic starter

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Receiving ultrasonic transducer picking up EM noise
« on: November 15, 2019, 05:01:03 pm »
Hi,
I am designing an ultrasonic receiver, to get data in 120-180 kHz bandwidth. My receiving transducer is connected to a commercial pre-amp (50dB gain). The transducer however is picking up noise about 150 mV peak-to-peak. Seems to be white noise.  What are the approaches to reduce the noise? I already covered the transducer with epoxy and it did help, but not much.

the pre-amp has adjustable filter bandwidth but increasing the filtering doesn't help, makes the noise worse
 

Offline KaneTW

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Re: Receiving ultrasonic transducer picking up EM noise
« Reply #1 on: November 15, 2019, 05:03:44 pm »
Check the power rails for SMPS noise. Shield the preamp, use coax or twisted pair for transducer cabling.
 


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