NVH microphone filter

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Calek
Newbie
Posts: 5
Joined: Thu Feb 25, 2021 3:20 pm

NVH microphone filter

Post by Calek »

Hi Guys,

I'm very happy to use picoscope for my test, easy to use and very small to carry out to the office.

I have a question for you, i need to save microphone wave on a different frequency but, i want to erase all the noise before starting my tests, how i can do it? I would start from 0dB to focus only the dB from the source under test withouth enviroment.

attached the noise before the test. PS: if i could start from 0G for the accelerometer, in the same condition will be perfect for my purpose.

Ciao
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Steve Smith
Pico Staff Member
Pico Staff Member
Posts: 1126
Joined: Sun Aug 25, 2013 7:22 am

Re: NVH microphone filter

Post by Steve Smith »

Hello and thank you for the post and your feedback using PicoScope/NVH

What you have described Calek is great new feature request that does not yet exist within our NVH software.
The ability to “zero out” ambient noise and vibration prior to recording could be very helpful indeed.
I will share this with the software team ASAP

In the meantime we have a number of ways to combat ambient noise which can be a real nuisance during post capture analysis

1. Using an accelerometer as a microphone is great for “listening” to audible structure borne frequencies up to 2000 Hz. (Ensure you inform the software you have a microphone connected as well as an accelerometer in order to expand the spectrum to 20 kHz)

For example, listening to wheel bearings can be achieved with a microphone but the ambient noise can become overwhelming

Attaching an accelerometer to the structure of interest (hub assembly in the example above) and listening to the captured data will remove a large proportion of ambient noise

We have discussed these techniques here:
post91701.html#p91701

Alternatively, you can Export your connected accelerometer data as a .wav file for playback in a 3rd party media player.
The following link will help topic21639.html

2. NVH filtering option
Using the NVH filtering feature we can remove the desired amount of ambient noise in order to focus on the frequencies of interest
The following forum post covers filtering within NVH post49441.html#p49441

3. Noise cancelation with 3rd party software
Here we export the captured data from PicoScope NVH and utilise the noise cancelation features of Audacity or Sonic Visualiser topic22151.html

Nosie cancelation works very well where your recording incorporates a passage of time where only ambient noise/vibration is present as this can be singled out during the cancelation process and then applied to the entire recording

I hope the above helps and thank you once again for your feedback

Take care……Steve

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