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Topic: Dominant Frequency problem
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angel61606



Joined: Jul 8, 2020
Posts: 26

PostPosted: Oct 27, 2020 5:41 AM    Post subject: Dominant Frequency problem

Hi Jarek
I am using Dominant frequency element to find the peak frequency between 0.04 to 0.26 Hz. i have passed my data from a band pass filter with those cut offs. But the dominant frequency elemnt doesn't work correctly. it sometimes shows frequency above 0.4.
I even changed the low and high frequency properties in Dominant frequency elemnt but still it didnt work. i tried to change fft bin count and input sample bins and also overlap bins nothing worked . please help me out. thanks
jarek



Joined: Oct 22, 2007
Posts: 829

PostPosted: Oct 27, 2020 11:57 AM    Post subject:

You may have to reconfigure it. The dominant frequency is based on FFT (Fast Fourier) transform, which has limitations.
angel61606



Joined: Jul 8, 2020
Posts: 26

PostPosted: Oct 28, 2020 9:41 AM    Post subject:

Jarek, how do you calculate the resolution? I mean the frequency resolution I expect is less than 0.1 Hz , considering the fact that my sampling rate is 250, i chose 4096 or 16384 for FFT bin count. but I see another parameter to be set here "input sample count", what do u mean by it? and how does it affect the resolution.
jarek



Joined: Oct 22, 2007
Posts: 829

PostPosted: Oct 28, 2020 5:20 PM    Post subject:

The "Input sample count" can be lower than FFT bin count. In such case the reminder is filled with 0 (zero) value. That can help with faster response time (when this is lower). Resolution is controlled by the number of FFT bins.
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