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Transient Response module questions.....

Creator
Creator

In the transient reponse module part of the setup involves setting Bandwidth, Spectral Lines and the Resolution.

 

What is the crtiteria for the proper adjustment of each on of those settings?

 

I am not clear on how or when to set the Bandwidth. And how does the relationship of one these settings affect the other settings? TIA

3 REPLIES

Re: Transient Response module questions.....

Siemens Legend Siemens Legend
Siemens Legend

Hello Chuck,

 

The Bandwidth should be set to a frequency about 25% above the maximum frequency of interest.  Due to the anti-aliasing filter, only about 80% of the Bandwidth (BW) is usable.    The BW / spectral lines = frequency resolution.  The inverse of the frequency resolution is the period for one FFT calculation, also called acquisition block time.  You should set the frequency resolution fine enough to capture the peak in the frequency domain function but not so fine so that the acquisition block time is excessively long. For example, with 1/8 Hz resolution, the acquisition block time would be 8 seconds long and anything happening faster than that would be missed.

 

There are some  interesting articles on digital signal processing on our Simcenter Testing Knowledge Base that you should check out:

There is a good article and video on aliasing here:  https://community.plm.automation.siemens.com/t5/Testing-Knowledge-Base/Aliasing/ta-p/367750

There is also one on the power spectral density (PSD) that discusses spectral lines and frequency resolution:  https://community.plm.automation.siemens.com/t5/Testing-Knowledge-Base/What-is-a-Power-Spectral-Dens...

 

 

 

Re: Transient Response module questions.....

Creator
Creator

Thanks for the info!

Re: Transient Response module questions.....

Siemens Genius Siemens Genius
Siemens Genius

Here is another article that may help explain Bandwidth, Spectral Lines and Resolution:

 

https://community.plm.automation.siemens.com/t5/Testing-Knowledge-Base/Digital-Signal-Processing-Sam...