Hioki 8841 - Transfer Function [TRF]

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8.7 FFT Analysis Function
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8.7.7 Transfer Function [TRF]
Function
Fb Fb
･
Fa* Gab
Hab = ── = ──── = ──
Fa Fa･Fa* Gaa
|Gab|
=── {cos(∠θb-∠θa) + jsin (∠θb-∠θa)}
|Gaa|
Horizontal
cursor
Vertical
cursor
Displays the transfer function (frequency characteristics) of the system being
measured calculated from input and output signals.
Nyquist diagrams can also be displayed, including magnitude and phase
information.
Major applications include:
・Determining filter frequency characteristics.
・Determining feedback control system stability through Nyquist diagrams.
・Determining the physical resonant frequency using an impulse hammer
and pick-up sensor.
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.
Real Linear display of the real-number part of the input-to-output
ratio (Nyquist mode)
RIN-REAL Linear display of the real-number part of the input-to-output
ratio (no units).
LIN-IMAG Linear display of the imaginary-number part of the input-to-
output ratio (no units).
LIN-MAG Linear display of input-to-output ratio (no units)
This expresses the amplitude component.
LOG-MAG Logarithmic display of input-to-output ratio as dB (no units)
This expresses the amplitude component.
PHASE Degrees (deg) display of phase component of data of input-to-
output ratio
Imag Linear display of the imaginary-number part of the input-to-
output ratio (Nyquist mode).