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david binkowski
Visitor II
May 5, 2020
Question

FFT explanation for PREDMNT1 software on STWIN

  • May 5, 2020
  • 1 reply
  • 693 views

Good morning,

I using STWIN for FFT analyse and i have few question about the data collection and especialy for understanding who does what

On STBLE app the logging from fft windows return 3 files (FFT amplitude, FFT and Motor time parameter). Is anybody have an explanation about their content for understanding how i can read and draw on excel the FFT.

By example what are the unit for amplitude column for file FFT ? how do the data are compiled?

i know that it exist design tips data sheet for sensortile but i haven't found yet for STWIN

thanks

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    1 reply

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    Eleon BORLINI
    ST Employee
    May 11, 2020

    Hi @david binkowski​ , this is the significance of the three files you get during the FFT log:

    • FFT: this file contains the sequence of all the FFT of the three axis x, y and z calculated during the FFT log.
      • Frequency= 0 indicates the start of a new FFT.
    • MotorTimeParameter: these parameters are the acc peak and the rms speed for the three axis and for each of the FFTs during the log time.
    • FFT amplitude: it contains the raw data of the calculated FFTs, and should not be kept into account for the data analysis. In detail:
      • RawData: 2byte /* nSample */ + 1 byte /* nComponents */ + 4 byte /* Frequency Steps */ + ((3 * Size) * 4) byte /* Samples (X1,X2, … Xn, Y1,Y2, … Yn, Z1,Z2, … Zn) */

    I believe that, since the STWIN kit is a very new tool, further online technical documentation will follow in the near future.

    Regards

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