Hioki Memory HiCorder MR6000, Instruction Manual, Page: 255 / 392

249
FFT Calculation Types
Power spectrum
The power spectrum calculates an input signal power of each frequency band and plots the
calculation results on a graph with a horizontal axis that indicates a frequency.
Main uses:
• To analyze peaks of frequency components of a waveform
• To analyze power levels of each frequency component
See “Calculation types and internal calculation formulas” (p. 254).
Axis Display type Description
Horizontal axis
(X-axis)
Linear Indicates a frequency on a linear scale.
Logarithmic Indicates a frequency on a logarithm scale.
Vertical axis
(Y-axis)
Amplitude (linear) Indicates a square of analyzed data. It represents power components.
Amplitude (decibel) Indicates analyzed data in decibels. (Reference of 0 dB: 1 eu
2
)*
* (Eu: engineering unit) The level is calculated using a reference value in terms with an engineering unit
presently set.
(For example, when the unit is set to volts, 0 dB is equivalent to 1 V
2
.)
Examples of waveforms
Normal display
Horizontal axis: logarithmic
Vertical axis: amplitude (linear)
Normal display
Horizontal axis: logarithmic
Vertical axis: amplitude (decibel)
The instrument with a cursor enabled displays the total harmonic distortion factor (THD) regarding
the cursor position as the fundamental wave. When displaying the two cursors, the instrument
regards the A cursor as the fundamental wave. When no results have been obtained, the instrument
displays the string [---%] .
FFT
Calculation Function
HIOKI MR6000A966-03