How to use FFT?

Log Analysis -- deprecated Copter Logs -- deprecated
1

I read that FFT can show frequency of vibration.
How to use it?
What is “Bins = 10”?
What is start Freq?
etc

Screenshot 2017-03-14 18.00.58.png1365×729 33.7 KB

2 1-1-2000 7-13-04 AM.bin (3.2 MB)

2

I tried to use FFT in Mission Planner 1.3.49 with my Pixhack with ArduPlane 3.8.0 and ArduCopter 3.5.2 (tried both) and no one was successful. When I tried to use “Run all imus ACC GYR MSG” or “Run Log - imu 1 ACC GYR MSG” I got error message and When I try “Run all imus IMUI1-3” I got no reaction at all. My LOG_BITMASK is 655358 “All+Full IMU” and Log graph shows it well.

Is there any requirements/restrictions for logs to show FFT graphs? Do I need only 3 imu turned on log to get it working? Should it be minimum run time for log to run properly?