What am I doing wrong with the FFT analysis?

ArduCopter Traditional Helicopter
1

I have reconfigured my scale Agusta109 (800 blades, 10kg, four blade) ( now less weight, less rpm).

After the first flight I wanted to do the Measuring Vibration with IMU Batch Sampler¶ as described in the wiki.

For this I had done the preparations as described in the wiki.

After the flight, I wanted to use the log in the FFTUI
to look at it. However, the displayed graph shows negative amplitude values.

FFT_Analyse1

Here ist he Bin-File:

What am I doing wrong?

Thank you for your help.

BR

Heri

2

It is very very normal to have negative numbers.

3

Nothing other than using a Log scale. If you want it to look like this then check the magnitude box before loading the log file:

fft
fft1251×955 85.2 KB

4

@dkemxr
@amilcarlucas

Thank you for your advice.

Life is so simple when you know what you have to do. :kissing_heart:

BR

Heri