Hioki Memory HiCorder MR6000, Instruction Manual, Page: 229 / 392

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9 FFT Calculation Function
9
FFT Calculation Function
Using the FFT function allows you to analyze input signal data with respect to frequency through
the FFT calculation.
This function is useful to perform frequency analysis of a variety of signals, such as those from
rotating objects, vibration, and sound.
See “16.2 FFT Definitions” (p. 371).
The instrument can perform FFT calculation using data previously obtained and processed through
waveform calculation, as well as that being acquired concurrently with measurement.
Using Model 8968 High Resolution Unit or Model 8979 Charge Unit, which are equipped with an
anti-aliasing filter, allows a cutoff frequency to automatically be set in conjunction with the frequency
range setting.
The FFT calculation function is not available in the following occasions:
• When the envelope is used
• When the real-time saving is set to [On]
Major features
• FFT calculation frequency range: 500 mHz to 100 MHz
• FFT calculation types (eight calculations)
FFT calculation type
Linear spectrum RMS spectrum
Power spectrum 1CH Phase spectrum
Cross power spectrum Transfer function
Coherence function 2CH Phase spectrum
• For FFT calculation using signals outputted from a sound level or vibration meter connected
with the instrument, you can directly read values in decibels processed through calibration by
configuring the scaling setting in the channel setting screen.
See “3.2 Converting Input Values (Scaling Function)” (p. 54).
To perform FFT calculations without being affected by aliasing distortion due to sampling
• Using an input module equipped with a anti-aliasing filter is recommended.
See “16.2 FFT Definitions” (p. 371), “Aliasing” (p. 373), and “Anti-aliasing filter” (p. 374).
• For more information about the specifications of the FFT calculation function, refer to Quick Start
Manual.
FFT
Calculation Function
HIOKI MR6000A966-03