PicoScope 7 Automotive
Available for Windows, Mac, and Linux, the next evolution of our diagnostic scope software is now available.
Analysing NVH data
Analysing NVH data
Hi all,
Been doing some recordings with my new NVH kit and I'm starting to get my head around it, but I have one question.
When you use the little "view" window (shown below), even when you reduce it to the minimum size, it still shows a "range".
Is there a way to show one "instance" eg: I want to see exactly how many mg I have at that specific RPM.
Also, when I expand the "window", is the MG readings shown an average for that period?
Been doing some recordings with my new NVH kit and I'm starting to get my head around it, but I have one question.
When you use the little "view" window (shown below), even when you reduce it to the minimum size, it still shows a "range".
Is there a way to show one "instance" eg: I want to see exactly how many mg I have at that specific RPM.
Also, when I expand the "window", is the MG readings shown an average for that period?
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Steve Smith
- Pico Staff Member
- Posts: 1586
- Joined: Sun Aug 25, 2013 7:22 am
Re: Analysing NVH data
Hello and thank you for the post.
Depending on the settings within the FFT you can amend the area of highlighted data in the Signal History.
By default you are correct that you cannot reduce this highlighted area to less than 2.5 seconds.
This is the amount of data required by the FFT to convert your captured signals into their appropriate frequencies and display them in the Frequency View.
This is why we aim to maintain vibrations/noises for 2.5 seconds whilst also keeping engine and roadside stable (Keep variables to a minimum) Not always possible I know, think of clutch judder during take-off!
If you wish to reduce this highlighted area to below 2.5 seconds then reduce the Response Setting in the image above.
The following forum post will explain the limitations of these settings and the compromises required. https://www.picoauto.com/support/topic17901-10.html#p82781
Just a quick note, the blue highlighter within the Signal History above has the Yellow Marker/Ruler to the left; this is your instantaneous RPM and Road Speed ruler where their respective numerical values are displayed (1810 rpm & 73 MPH)
For Instantaneous measurement of amplitude (One Instance) you can switch to the Time Domain View.
Below I have selected 10 seconds of interest in the Signal History (230-240 seconds)
I can then measure the instantaneous amplitude (in mg) at any time during my selected 10 seconds. I have chosen to measure at 235 seconds but you could choose 230 seconds which is directly beneath the Yellow RPM/Road Speed Marker/Ruler
More applications of the Time Domain can be found here:
https://www.picoauto.com/support/topic13221.html
https://www.picoauto.com/support/topic21061.html
Could you download the latest version of PicoScope to take full advantage of the Time Domain and other new features?
https://www.picoauto.com/downloads
https://www.picoauto.com/support/topic21639.html
With regards to: “Also, when I expand the "window", is the MG readings shown an average for that period?”
This depends on your chosen Display Mode and initial Set up.
Highlight the area of interest in your Signal History and then “right click” on the Frequency View screen. This will open another menu where you can select the Display Mode.
You now have a choice on how you wish to view the data, “Vector Sum” if you are using a 3 Axis Accelerometer with a TA259 Interface, “Single View”, “Peak View” or “Average View”
I hope this helps and please feedback for any clarification
Take care……Steve
Depending on the settings within the FFT you can amend the area of highlighted data in the Signal History.
By default you are correct that you cannot reduce this highlighted area to less than 2.5 seconds.
This is the amount of data required by the FFT to convert your captured signals into their appropriate frequencies and display them in the Frequency View.
This is why we aim to maintain vibrations/noises for 2.5 seconds whilst also keeping engine and roadside stable (Keep variables to a minimum) Not always possible I know, think of clutch judder during take-off!
- Signal History
The following forum post will explain the limitations of these settings and the compromises required. https://www.picoauto.com/support/topic17901-10.html#p82781
Just a quick note, the blue highlighter within the Signal History above has the Yellow Marker/Ruler to the left; this is your instantaneous RPM and Road Speed ruler where their respective numerical values are displayed (1810 rpm & 73 MPH)
For Instantaneous measurement of amplitude (One Instance) you can switch to the Time Domain View.
Below I have selected 10 seconds of interest in the Signal History (230-240 seconds)
I can then measure the instantaneous amplitude (in mg) at any time during my selected 10 seconds. I have chosen to measure at 235 seconds but you could choose 230 seconds which is directly beneath the Yellow RPM/Road Speed Marker/Ruler
- Time Domain
https://www.picoauto.com/support/topic13221.html
https://www.picoauto.com/support/topic21061.html
Could you download the latest version of PicoScope to take full advantage of the Time Domain and other new features?
https://www.picoauto.com/downloads
https://www.picoauto.com/support/topic21639.html
With regards to: “Also, when I expand the "window", is the MG readings shown an average for that period?”
This depends on your chosen Display Mode and initial Set up.
Highlight the area of interest in your Signal History and then “right click” on the Frequency View screen. This will open another menu where you can select the Display Mode.
- Display Mode
I hope this helps and please feedback for any clarification
Take care……Steve