Hioki MEMORY HiCORDER 8855, Instruction Manual

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4.8 FFT Analysis Function
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4.8.11 Coherence [COH]
Function
Gab* Gab
COH =
Gaa Gbb
Horizontal
cursor
Vertical
cursor
NOTE
Stored waveform (input signal) Stored waveform (output signal)
Coherence
Displays the output signal component that is coherent (interference possible)
to the input signal, yielding a value from 0 to 1.
Major applications include:
Evaluation of transfer functions.
Determining the contribution of individual input lines to the output of
multi-input systems.
LIN-Hz Frequency spectrum display as linear units. The range is from
DC to the maximum frequency range value.
LOG-Hz Frequency spectrum display as logarithmic units. The range is
from between 1/400 and 1/4000 of value to the frequency
range value.
Linear The relationship between the two input signals. The degree of
relationship is indicated from 0 to 1 on a linear scale (no
units).
For a single measurement, the coherence function returns 1 for all
frequencies. When measuring, be sure to use frequency averaging.
Example Coherence function waveforms