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06
't4
22
30
38
05
13
21
29
37
m
11
19
27
35
01
09
17
25
33
110
v(w1)
CV(W1,e1)
v(w2)
DAY
v(u1)
cR(w1,u1)
v(u2)
M(u1)
V(e1)
M(U2)
V(e2)
SECTION
8.
PROCESSING
AND PROGRAM CONTROL EXAMPLES
TABLE
8.7'4.
Thirty Minute Output From Example
M(V1)
07
MCrai)
08
cv(w1,u1) 1s
cv(wl,vl)
16
M(V2)
m MCra2)
24
cv(w2,u2)
31
CV(W2,V2)
32
,v2')
CV(U2,Ta2) 36
HRMIN
04
MWl)
V(V1)
12
Vfial)
cR(wr,v1) 20
M(w2)
V(V2)
28
v[az)
M(el)
CV(W1,Ta1)
M(e2)
CV(W2,Ta2)
and
8.8-3 respectively. A portion of the power
spectra results are illustrated in Figure 8.8-2.
The phase
of
the cosine wave that describes the
signat
atthe
beginning of the
firsl
interval and
the
endof the
last
intervalcan
be determined by
looking
at
the
21X program
flable
5)
that
generated
the "originaltime series
data".
The
1.25H2 signalbegan and ended at27O
degrees.
[cos 270
=
cos(O -
90)
= sin
0].
The
O-ZStlzsignalbegan
at27O degrees and ended
at 126
degrees. The
phases
ofthe
1.25
and
0.25 signals
are27O and 198 respectively fl-able
8.8-2).
FFT
ANALYSIS
OF
0.25 AND
1
.25
Hz
SIGNAL
o.9
,,^
0,6
3i
--
i
o.r
6t
<3
o.a
ol
o.7
o7
d
o.rcsu
o.J96a
o$596
o.7ol26
o976
l.r7192
IJ6724
FntMKl
rN
h
=
6rS
O TO 150
FIGURE
8.8-2.
FFT Power
Spectra Analysis
of 0.25 and
1.25 Hz
Signal
8.8' FAST
FOURIER TRANSFORM
EXAMPLES
8.8.1.
BIN
AVERAGING
The 21X was
to generate data
representing
two superimposed sine wave
signals,
one
4
1.25H2 (amplitude_=
1)
and the
shows
a plot
Sf
the simulated
signal.
Th
was applied
t{
the data and the real and
imaginary, phpse and magnitude, and
th
spectra result$ are shown
in
Tables 8.8-
other at
0.25 Hz (amplitude
=
2).
The 1024
generated
simulate
a
samPling
rate of
iO
Hz
or
a
0.'l
second
scan
rale.
Figure
8.8-1
shows
a plot
Sf
the simulated
signal. The
FFT
imaginary, phpse and magnitude, and
the power
speitra resuftt
are shown
in
Tables 8.8-1, 8.8-2,
FIGURE
8.&1.
Simulated
1.25
and O.25Hz
Signals
&11
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