User Manual

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8.7 Analysis Function
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8
.7.5 Auto Correlation [ACR]
Functio
n
Raa (τ)=
-1
(Gaa)
= Gaa (ω)exp(jωτ)dω
Horizonta
l
curso
r
Vertica
l
curso
r
Vertical axis Display
LIN-REAL (real-number part) −
LIN-IMAG (imaginary-number part) −
LIN-MAG (amplitude) Raa
LOG-MAG (logarithmic amplitude) −
PHASE (phase) −
S
tored waveform
A
uto correlation functio
n
Displays the degree of similarity between two points in the input signal separated
by time difference (τ).
Major applications:
・Detecting a periodic signal contained in a noisy signal with an improvement in
signal-to-noise ratio.
・Checking the periodic signal components contained in a noisy waveform, and
periodic noise.
Time Time display. The center indicates the reference (τ=0), the right
side indicates time lag (+τ), and the left side indicates time lead
(-τ).
Linear Readings are between +1 and -1 (without units).
+1: the highest similarity for time differential τ
0: the lowest similarity, -1: the polarity is completely opposite.
Due to the characteristics of the function, τ=0 always results in
+1.
Example Auto correlation function waveforms 08-65, 38