Fourier MultiLogPRO User Manual page 81

=
y
Derivative
n
Draws a line of the slopes of every three consecutive points of a data
set. For high recording rates and small Δt, this line may be very noisy,
which is why smoothing the data set is recommended before applying
the derivative function.
AG
y =
Divide
BG
Draws a line of the division of two data sets
Envelope
Lower envelope of G
(lower)
Draws a line that connects the minimum values of a data set. The
tolerance defines the minimum distance (in sampling points) between
two minima, so that the envelope function is able to ignore random
noises.
Envelope
Upper envelope of G
(upper)
Draws a line that connects the maximum values of a data set. The
tolerance defines the minimum distance (in sampling points) between
two maxima, so that the envelope function will be able to ignore
random noises.
=
Exp.
y Ae
Draws a line of
Fourier
Discrete Fourier transform of G
transform
Draws a line of the amplitudes of the harmonics of Fourier transform
vs. frequency.
Frequency
The frequency of G1 (minimum of A points in one cycle).
Draws a line of the frequency of a periodic data set vs. time. The
constant A defines the minimum data points in one cycle.
=
Integral y A
Draws a line in which each point is the discrete integral of all the
preceding points in a data set.
72 Chapter 2 MultiLab Software
−
y y
+ − Δ =
n 1 n 1
, t
Δ
2 t sampling
1
2
with tolerance of A points
1
with tolerance of A points
1
BG +
C
1
e
raised to the power of a data set.
∑
+ Δ
B G t
1
1
rate
.
1