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2
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m
a
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o
n
[
6
]
,
[
9
]
.
S
e
v
e
r
a
l
s
t
u
d
i
e
s
h
a
v
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d
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f
a
s
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f
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r
i
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r
t
r
a
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s
f
o
r
m
(
F
F
T
)
–
b
a
s
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d
s
i
g
n
a
l
a
n
a
l
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s
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c
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k
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an
d
m
o
s
q
u
i
t
o
e
s
[
7
]
,
[
10]
–
[
1
2
]
.
O
t
h
e
r
s
t
u
d
i
es
h
a
v
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to
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t
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o
(
S
NR
)
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r
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l
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l
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s
p
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p
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n
s
[
6
]
.
A
m
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g
v
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s
f
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l
t
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t
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,
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f
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l
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m
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p
ass
b
a
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d
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p
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it
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k
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a
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r
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t
y
[
1
1
]
,
[
1
3
]
.
H
o
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F
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B
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,
h
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a
b
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ic
s
s
t
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d
i
es
[
8
]
.
B
i
o
a
c
o
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s
t
i
cs
h
a
s
b
e
c
o
m
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ty
,
a
s
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f
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al
a
n
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l
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s
is
[
7
]
,
[
1
4
]
,
[
1
5
]
.
A
co
u
s
t
i
c
s
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g
n
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a
n
a
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a
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d
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c
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s
ti
c
c
a
l
ls
[
2
]
,
[
7
]
,
[
1
5
]
–
[
1
7
]
.
I
n
a
g
r
i
c
u
l
t
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r
a
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c
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c
t
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c
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c
l
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s
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s
[
1
8
]
.
F
F
T
m
e
t
h
o
d
s
a
r
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w
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d
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a
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t
s
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d
s
[
2
]
,
[
7
]
,
[
1
5
]
,
[
1
6
]
.
I
n
t
e
r
n
a
t
i
o
n
a
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c
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as
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c
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c
a
d
as
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n
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o
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h
er
s
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e
c
i
es
[
1
]
,
[
3
]
,
[
1
5
]
.
I
n
p
ar
a
l
l
e
l
,
B
u
tt
e
r
w
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t
h
b
a
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a
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f
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y
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e
s
p
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n
s
e
[
6
]
,
[
1
1
]
,
[
1
9
]
.
F
u
r
t
h
e
r
m
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a
c
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m
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a
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p
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B
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t
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a
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[
6
]
,
[
1
9
]
.
S
t
u
d
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c
o
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d
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c
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d
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n
d
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d
.
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a
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u
d
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F
F
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-
b
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a
p
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c
c
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a
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r
i
z
at
i
o
n
[
2
0
]
,
[
2
1]
.
I
n
a
d
d
i
t
i
o
n
,
s
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a
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p
r
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r
t
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c
l
a
s
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f
ic
a
t
i
o
n
[
2
2
]
.
T
h
e
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f
i
n
d
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s
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d
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c
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a
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.
T
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T
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B
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3
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.
R
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[
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[
1
5
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1
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]
.
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a
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2
4
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2.
M
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to
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I
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N
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I
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d
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J
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&
C
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p
Sci
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Vo
l.
42
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3
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J
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20
26
:
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Fig
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r
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1
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Fig
u
r
e
1
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Flo
wch
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t
o
f
t
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r
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s
2
.
1
.
Da
t
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it
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Gr
ass
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[
8
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[
1
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,
[
1
4
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.
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Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
d
o
n
esian
J
E
lec
E
n
g
&
C
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m
p
Sci
I
SS
N:
2502
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4
7
5
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[
2
5
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Similar
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ies
[
1
]
,
[
2
6
]
.
Fig
u
r
e
3
p
r
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a
10
-
s
ec
o
n
d
s
eg
m
en
t
ex
tr
ac
te
d
f
r
o
m
th
e
o
r
ig
in
al
1
2
0
-
s
ec
o
n
d
g
r
ass
h
o
p
p
er
s
o
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n
d
r
ec
o
r
d
in
g
.
T
h
is
s
eg
m
en
tatio
n
s
tep
is
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ec
ess
ar
y
to
s
tan
d
ar
d
i
ze
s
ig
n
al
len
g
th
an
d
f
ac
ilit
ate
co
n
s
is
ten
t
s
p
ec
tr
al
an
aly
s
is
ac
r
o
s
s
m
u
ltip
le
s
am
p
les.
T
h
e
wav
ef
o
r
m
s
till
ex
h
ib
i
ts
n
o
is
e
co
n
tam
in
atio
n
,
em
p
h
a
s
izin
g
th
e
n
ee
d
f
o
r
f
u
r
th
er
p
r
ep
r
o
ce
s
s
in
g
an
d
f
ilter
in
g
to
is
o
late
th
e
g
r
ass
h
o
p
p
e
r
ac
o
u
s
tic
co
m
p
o
n
en
ts
.
Fig
u
r
e
3
.
Gr
ass
h
o
p
p
er
s
o
u
n
d
s
ig
n
al
f
o
r
1
0
s
ec
o
n
d
s
2
.
3
.
Sp
ec
t
ra
l
a
na
ly
s
is
(
bef
o
re
f
ilte
ring
)
E
ac
h
s
eg
m
en
t
was
an
aly
ze
d
u
s
in
g
th
e
FF
T
to
o
b
tain
a
f
r
eq
u
en
cy
s
p
ec
tr
u
m
[
1
0
]
,
[
1
6
]
.
Do
m
in
an
t
f
r
eq
u
e
n
cy
p
ea
k
s
an
d
h
ar
m
o
n
i
c
p
atter
n
s
wer
e
ex
am
in
ed
to
d
is
tin
g
u
is
h
g
r
ass
h
o
p
p
er
ca
lls
f
r
o
m
en
v
ir
o
n
m
en
tal
s
o
u
n
d
s
[
1
7
]
.
T
h
is
ap
p
r
o
ac
h
is
co
n
s
is
ten
t
with
e
s
tab
lis
h
e
d
a
co
u
s
tic
s
ig
n
al
an
aly
s
is
m
eth
o
d
s
ap
p
lied
in
in
s
ec
t
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d
en
v
ir
o
n
m
en
tal
s
o
u
n
d
cl
ass
if
icatio
n
s
tu
d
ies
[
7
]
,
[
1
5
]
,
[
1
9
]
.
T
h
e
f
iv
e
h
ig
h
est
f
r
eq
u
en
cy
p
ea
k
s
wer
e
id
en
tifie
d
to
esti
m
ate
th
e
ch
ar
ac
ter
is
tic
f
r
eq
u
en
cy
r
a
n
g
e
o
f
th
e
g
r
ass
h
o
p
p
er
ca
lls
.
I
n
ad
d
itio
n
,
th
e
tim
e
–
f
r
eq
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e
n
cy
r
elatio
n
s
h
i
p
was a
n
aly
ze
d
u
s
in
g
a
s
p
ec
tr
o
g
r
a
m
to
m
o
n
ito
r
s
ig
n
al
d
y
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a
m
ics.
Fig
u
r
e
4
s
h
o
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e
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r
eq
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en
c
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o
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ai
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ig
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o
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e
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ilter
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T
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e
s
p
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tr
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m
r
ev
ea
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m
u
lti
p
le
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r
eq
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ates
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ib
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Alth
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m
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t
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to
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o
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p
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o
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s
tic
ch
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ac
ter
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tics
ch
allen
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in
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.
Fig
u
r
e
4
.
(
L
ef
t)
s
p
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m
an
d
(
R
ig
h
t)
Sp
ec
to
g
r
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o
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ass
h
o
p
p
er
s
o
u
n
d
s
ig
n
al
b
ef
o
r
e
f
ilte
r
in
g
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
5
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4
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I
n
d
o
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J
E
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&
C
o
m
p
Sci
,
Vo
l.
42
,
No
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3
,
J
u
n
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20
26
:
7
0
8
-
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2
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712
2
.
4
.
Det
er
m
ini
ng
f
ilte
r
pa
ra
m
et
er
s
T
h
e
B
u
tter
wo
r
th
f
ilter
was
s
elec
ted
d
u
e
to
its
m
ax
im
ally
f
l
at
m
ag
n
itu
d
e
r
esp
o
n
s
e
i
n
th
e
p
ass
b
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d
,
wh
ich
m
in
im
izes
am
p
litu
d
e
d
is
to
r
tio
n
o
f
b
io
l
o
g
i
ca
lly
r
ele
v
an
t
ac
o
u
s
tic
s
ig
n
als
[
1
1
]
.
U
n
lik
e
C
h
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y
s
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o
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ellip
tic
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ilter
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wh
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o
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ce
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ass
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ip
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ase
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lar
ities
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B
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tter
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r
th
f
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s
p
r
o
v
id
e
s
m
o
o
th
er
s
p
ec
tr
al
p
r
eser
v
atio
n
,
m
a
k
in
g
th
em
m
o
r
e
s
u
itab
le
f
o
r
b
io
ac
o
u
s
tic
s
ig
n
al
an
aly
s
is
wh
er
e
wa
v
ef
o
r
m
in
te
g
r
ity
is
im
p
o
r
tan
t
[
2
5
]
.
T
h
er
ef
o
r
e,
t
h
e
B
u
tter
wo
r
th
f
ilter
r
ep
r
esen
ts
a
b
alan
ce
d
tr
a
d
e
-
o
f
f
b
etwe
en
s
p
ec
tr
al
ac
cu
r
ac
y
,
co
m
p
u
tatio
n
al
e
f
f
icien
cy
,
an
d
im
p
lem
en
tatio
n
s
im
p
licity
f
o
r
p
r
ac
tical
b
io
ac
o
u
s
tic
ap
p
licatio
n
s
[
1
1
]
,
[
2
5
]
.
T
h
e
B
u
tter
wo
r
th
f
ilter
p
ar
am
eter
s
wer
e
ca
lcu
lated
an
d
im
p
lem
en
ted
u
s
in
g
Ma
tlab
s
o
f
t
war
e.
T
h
e
d
esig
n
p
ar
am
eter
s
in
clu
d
e
th
e
b
an
d
p
ass
f
r
eq
u
en
cy
r
an
g
e,
d
ef
in
ed
b
y
th
e
lo
wer
-
s
id
e
an
d
u
p
p
e
r
-
s
id
e
cu
to
f
f
f
r
eq
u
e
n
cies,
an
d
th
e
f
ilter
o
r
d
er
.
T
h
e
f
r
eq
u
e
n
cy
r
a
n
g
e
was
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eter
m
in
ed
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ased
o
n
t
h
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o
m
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t
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p
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tr
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p
ea
k
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b
tain
ed
f
r
o
m
FF
T
an
aly
s
is
[
1
0
]
,
with
an
a
d
d
itio
n
al
±
2
0
%
m
ar
g
in
to
d
e
f
in
e
th
e
p
ass
b
an
d
lim
its
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T
h
e
f
ilter
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s
d
esig
n
ed
with
o
r
d
er
v
ar
i
atio
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s
r
an
g
in
g
f
r
o
m
4
to
8
to
ev
alu
ate
th
e
tr
ad
e
-
o
f
f
b
etwe
en
n
o
is
e
s
u
p
p
r
ess
io
n
p
er
f
o
r
m
an
ce
an
d
co
m
p
u
tatio
n
al
co
m
p
lex
ity
[
1
1
]
,
[
2
5
]
.
T
h
e
±
2
0
%
m
ar
g
i
n
ar
o
u
n
d
th
e
d
o
m
in
an
t
f
r
e
q
u
en
c
y
p
ea
k
s
was
d
eter
m
in
ed
em
p
ir
ically
b
ased
o
n
r
ep
ea
ted
FF
T
o
b
s
er
v
atio
n
s
ac
r
o
s
s
m
u
ltip
le
r
ec
o
r
d
in
g
s
eg
m
en
ts
.
T
h
is
m
ar
g
in
ac
co
m
m
o
d
ates n
atu
r
al
f
r
eq
u
en
c
y
v
ar
iab
ilit
y
ca
u
s
ed
b
y
i
n
s
ec
t
m
o
v
em
en
t,
win
g
b
ea
t
i
n
ten
s
ity
,
an
d
en
v
ir
o
n
m
en
tal
co
n
d
itio
n
s
.
Similar
v
ar
iab
ilit
y
in
in
s
ec
t a
co
u
s
tic
f
r
eq
u
e
n
cy
c
h
ar
ac
ter
is
tics
h
as b
ee
n
r
ep
o
r
ted
in
b
io
ac
o
u
s
tic
s
tu
d
ies
[
1
2
]
.
2
.
5
.
F
ilte
ring
pro
ce
s
s
Fig
u
r
e
5
co
m
p
ar
es
th
e
g
r
ass
h
o
p
p
er
s
o
u
n
d
s
ig
n
al
b
ef
o
r
e
an
d
af
ter
B
u
tter
wo
r
th
b
an
d
p
ass
f
ilter
in
g
in
b
o
th
t
h
e
tim
e
d
o
m
ai
n
(
lef
t
)
a
n
d
f
r
eq
u
e
n
cy
d
o
m
ai
n
(
r
ig
h
t)
.
Af
ter
f
ilter
in
g
,
t
h
e
tim
e
-
d
o
m
ain
s
ig
n
al
e
x
h
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its
r
ed
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ce
d
a
m
p
litu
d
e
v
ar
iab
ili
ty
,
wh
ile
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e
f
r
e
q
u
en
c
y
-
d
o
m
ain
r
ep
r
esen
tatio
n
s
h
o
w
s
clea
r
er
s
p
ec
tr
al
co
n
ce
n
tr
atio
n
with
in
th
e
tar
g
et
b
an
d
.
T
h
is
co
m
p
ar
is
o
n
d
em
o
n
s
tr
ates th
e
ef
f
ec
tiv
en
ess
o
f
th
e
B
u
tter
wo
r
th
f
ilter
in
s
u
p
p
r
ess
in
g
o
u
t
-
of
-
b
an
d
n
o
i
s
e
wh
ile
p
r
eser
v
in
g
r
ele
v
an
t sig
n
al
co
m
p
o
n
e
n
ts
.
-
Ap
p
ly
a
B
u
tter
wo
r
th
f
ilter
b
y
en
ter
in
g
t
h
e
p
r
e
v
io
u
s
ly
ca
lc
u
lated
p
ar
am
eter
v
alu
es,
n
am
el
y
th
e
u
p
p
e
r
-
s
id
e
f
r
eq
u
e
n
cy
,
lo
wer
-
s
id
e
f
r
eq
u
en
cy
,
an
d
f
ilter
o
r
d
er
.
-
Vis
u
aliza
tio
n
o
f
th
e
f
ilter
ed
s
i
g
n
al
is
p
lo
tted
in
th
e
tim
e
d
o
m
ain
to
s
ee
th
e
d
if
f
e
r
en
ce
in
am
p
litu
d
e.
-
Vis
u
aliza
tio
n
o
f
th
e
f
ilter
ed
s
i
g
n
al
s
p
ec
tr
u
m
is
p
lo
tted
to
ass
ess
th
e
s
u
cc
ess
o
f
n
o
is
e
atten
u
atio
n
.
Fig
u
r
e
5
.
Gr
ass
h
o
p
p
er
s
o
u
n
d
s
ig
n
al
b
ef
o
r
e
an
d
af
ter
f
ilter
in
g
(
lef
t)
tim
e
d
o
m
ain
(
r
i
g
h
t)
s
p
e
ctr
u
m
at
f
r
e
q
u
en
c
y
d
o
m
ain
2
.
6
.
Q
ua
ntit
a
t
iv
e
pa
r
a
m
e
t
er
ca
lcula
t
io
n
Fig
u
r
e
6
d
is
p
lay
s
th
e
Ma
tl
ab
in
ter
f
ac
e
u
s
ed
f
o
r
q
u
an
t
itativ
e
p
ar
am
eter
ex
tr
ac
tio
n
,
in
clu
d
in
g
r
ec
o
r
d
in
g
d
u
r
atio
n
,
Ny
q
u
is
t
f
r
eq
u
en
cy
,
d
o
m
in
an
t
f
r
eq
u
en
cy
r
a
n
g
e,
l
o
wer
-
s
id
e
an
d
u
p
p
e
r
-
s
id
e
b
a
n
d
f
r
eq
u
e
n
cies,
f
ilter
o
r
d
er
,
an
d
SNR
v
alu
es.
T
h
is
F
ig
u
r
e
6
h
i
g
h
lig
h
ts
th
e
s
y
s
tem
atic
an
d
r
ep
e
atab
le
n
atu
r
e
o
f
th
e
an
aly
s
is
p
r
o
ce
s
s
,
en
s
u
r
in
g
tr
a
n
s
p
ar
en
cy
an
d
r
ep
r
o
d
u
cib
ilit
y
o
f
th
e
p
r
o
p
o
s
ed
s
ig
n
al
p
r
o
ce
s
s
in
g
f
r
a
m
ewo
r
k
.
Step
s
tak
en
to
ca
lcu
late
q
u
a
n
titativ
e
p
ar
am
eter
s
:
−
C
alcu
latin
g
th
e
(
SNR
in
g
en
er
al)
.
−
B
an
d
-
b
ased
SNR
(
in
-
b
an
d
v
s
.
o
u
t
-
of
-
b
an
d
)
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
d
o
n
esian
J
E
lec
E
n
g
&
C
o
m
p
Sci
I
SS
N:
2502
-
4
7
5
2
Gra
s
s
h
o
p
p
er so
u
n
d
a
c
o
u
s
tic
s
ig
n
a
l a
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s
u
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in
g
fft a
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u
tter
w
o
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th
filt
er
(
K
h
a
ir
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713
−
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alcu
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an
d
p
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s
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g
th
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elch
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ess
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ib
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e
r
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r
eq
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en
cy
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−
C
o
m
p
ar
in
g
Fil
ter
Or
d
er
s
.
Fil
te
r
s
wer
e
test
ed
at
o
r
d
er
s
4
–
8
to
d
eter
m
in
e
th
eir
e
f
f
ec
t o
n
SNR
an
d
PS
D.
−
C
o
m
p
ar
in
g
th
e
SNR
an
aly
s
is
r
esu
lts
to
r
ec
o
r
d
in
g
d
u
r
atio
n
s
o
f
1
0
,
1
5
,
2
0
,
a
n
d
2
5
s
ec
o
n
d
s
.
Fig
u
r
e
6
.
Dis
p
lay
o
f
in
p
u
t a
n
d
o
u
tp
u
t
p
ar
am
eter
s
in
th
e
MA
T
L
AB
win
d
o
w.
I
t
s
h
o
ws
th
e
v
alu
es: Du
r
atio
n
o
f
th
e
g
r
ass
h
o
p
p
e
r
ac
o
u
s
tic
s
ig
n
a
l,
Ny
q
u
is
t f
r
eq
u
en
cy
,
d
o
m
i
n
an
t f
r
eq
u
e
n
cy
r
a
n
g
e
at
th
e
5
h
ig
h
est am
p
litu
d
es,
L
SB
an
d
USB
f
r
eq
u
en
cies,
f
ilter
o
r
d
e
r
,
SNR
b
ef
o
r
e
a
n
d
af
ter
f
ilter
in
g
(
SNR
b
ef
o
r
e
an
d
a
f
ter
b
ein
g
a
p
p
lied
to
th
e
PS
D
m
eth
o
d
with
th
e
W
elch
ap
p
r
o
ac
h
)
2
.
7
.
V
a
lid
a
t
i
o
n
da
n
ev
a
lua
t
i
o
n
T
h
e
r
esu
lts
o
f
SNR
ca
lcu
latio
n
s
u
s
in
g
d
if
f
er
e
n
t p
ar
am
eter
s
wer
e
co
m
p
ar
e
d
with
r
ef
er
en
c
e
r
ec
o
r
d
in
g
s
o
f
g
r
ass
h
o
p
p
er
s
th
at
h
ad
b
ee
n
v
is
u
ally
v
er
if
ied
in
th
e
f
iel
d
.
Fig
u
r
e
7
p
r
esen
ts
a
co
m
p
ar
is
o
n
o
f
th
e
PS
D
b
ef
o
r
e
an
d
af
ter
f
ilter
in
g
.
T
h
e
f
ilte
r
ed
PS
D
s
h
o
ws
a
s
tr
o
n
g
c
o
n
ce
n
tr
atio
n
o
f
en
er
g
y
with
in
th
e
g
r
ass
h
o
p
p
er
’
s
d
o
m
in
an
t
f
r
e
q
u
en
c
y
b
an
d
,
w
h
ile
en
er
g
y
o
u
ts
id
e
t
h
is
r
an
g
e
is
s
ig
n
if
ic
an
tly
atten
u
ated
.
T
h
is
r
esu
lt
co
n
f
ir
m
s
th
at
PS
D
-
b
ased
an
aly
s
is
p
r
o
v
id
es
a
m
o
r
e
r
e
p
r
esen
tativ
e
ass
es
s
m
en
t
o
f
s
p
ec
tr
al
clar
it
y
th
an
d
ir
ec
t
tim
e
-
d
o
m
ain
SNR
.
Fig
u
r
e
7
.
PSD
co
m
p
a
r
is
o
n
b
ef
o
r
e
an
d
af
ter
f
ilter
in
g
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
5
0
2
-
4
7
5
2
I
n
d
o
n
esian
J
E
lec
E
n
g
&
C
o
m
p
Sci
,
Vo
l.
42
,
No
.
3
,
J
u
n
e
20
26
:
7
0
8
-
7
2
0
714
3.
RE
SU
L
T
S AN
D
D
I
SCU
SS
I
O
N
T
h
e
r
esu
lts
o
f
th
e
ca
lcu
latio
n
an
aly
s
is
with
v
ar
iatio
n
s
in
r
ec
o
r
d
in
g
d
u
r
atio
n
a
r
e
p
r
esen
ted
in
T
ab
les
1
-
4.
Alth
o
u
g
h
r
ec
o
r
d
i
n
g
s
wer
e
o
b
tain
e
d
f
r
o
m
a
s
in
g
le
ag
r
icu
ltu
r
al
l
o
ca
tio
n
,
r
o
b
u
s
tn
ess
wa
s
p
ar
tially
ev
alu
ated
t
h
r
o
u
g
h
r
ep
ea
te
d
a
n
aly
s
is
u
s
in
g
m
u
ltip
le
r
ec
o
r
d
in
g
d
u
r
atio
n
s
(
1
0
–
2
5
s
)
a
n
d
f
ilte
r
o
r
d
er
s
(
4
–
8
)
.
T
h
e
co
n
s
is
ten
t
tr
en
d
o
b
s
er
v
ed
in
PS
D
-
b
ased
SNR
im
p
r
o
v
em
e
n
t
ac
r
o
s
s
th
ese
v
ar
iatio
n
s
in
d
icate
s
m
eth
o
d
o
l
o
g
ical
s
tab
ilit
y
u
n
d
er
d
if
f
e
r
en
t
s
ig
n
al
co
n
d
itio
n
s
.
Fig
u
r
e
8
illu
s
tr
ates
th
e
co
m
p
ar
is
o
n
o
f
SNR
v
alu
es
b
ef
o
r
e
an
d
a
f
ter
f
ilter
in
g
f
o
r
a
1
0
-
s
ec
o
n
d
r
ec
o
r
d
in
g
d
u
r
atio
n
.
Alth
o
u
g
h
th
e
d
ir
ec
t
SNR
s
lig
h
tly
d
ec
r
ea
s
es
af
ter
f
ilter
in
g
,
th
e
f
ig
u
r
e
d
e
m
o
n
s
tr
ates th
at
tim
e
-
d
o
m
ain
SNR
alo
n
e
d
o
es n
o
t f
u
lly
ca
p
tu
r
e
s
p
ec
tr
al
im
p
r
o
v
e
m
en
t,
r
ein
f
o
r
cin
g
th
e
n
ee
d
f
o
r
PS
D
-
b
ased
e
v
alu
atio
n
.
T
ab
le
1
.
SNR
ca
lcu
latio
n
r
esu
lts
o
f
g
r
ass
h
o
p
p
er
s
o
u
n
d
s
r
ec
o
r
d
ed
f
o
r
1
0
s
ec
o
n
d
s
P
a
r
a
me
t
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r
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0
s
e
c
o
n
d
s
d
o
m
i
n
a
n
t
f
r
e
q
u
e
n
c
y
r
a
n
g
e
5
9
6
8
H
z
–
8
9
9
4
H
z
F
i
l
t
e
r
o
r
d
e
r
4
5
6
7
8
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N
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b
e
f
o
r
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f
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l
t
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(
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6
,
7
8
7
9
6
,
7
3
8
2
6
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7
0
7
7
6
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6
8
7
6
6
,
6
7
3
5
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R
a
f
t
e
r
f
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l
t
e
r
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n
g
(
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)
5
,
5
7
3
9
5
,
5
4
7
6
5
,
5
3
2
7
5
,
5
2
3
9
5
,
5
1
8
5
S
N
R
P
S
D
b
e
f
o
r
e
f
i
l
t
e
r
i
n
g
(
d
B
)
5
,
5
0
2
5
,
5
0
2
5
,
5
0
2
5
,
5
0
2
5
,
5
0
2
S
N
R
P
S
D
a
f
t
e
r
f
i
l
t
e
r
i
n
g
(
d
B
)
2
5
,
0
1
3
7
2
5
,
9
8
5
2
2
6
,
7
5
4
7
2
7
,
3
9
2
5
2
7
,
9
3
6
3
T
ab
le
2
.
SNR
ca
lcu
latio
n
r
esu
lts
o
f
g
r
ass
h
o
p
p
er
s
o
u
n
d
s
r
ec
o
r
d
ed
f
o
r
1
5
s
ec
o
n
d
s
P
a
r
a
me
t
e
r
G
r
a
ssh
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p
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s
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n
d
r
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c
o
r
d
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g
f
o
r
1
5
s
e
c
o
n
d
s
d
o
m
i
n
a
n
t
f
r
e
q
u
e
n
c
y
r
a
n
g
e
5
8
4
9
H
z
-
8
9
7
7
H
z
F
i
l
t
e
r
o
r
d
e
r
4
5
6
7
8
S
N
R
b
e
f
o
r
e
f
i
l
t
e
r
i
n
g
(
d
B
)
7
,
0
2
3
2
6
,
9
6
2
1
6
,
9
2
3
1
6
,
8
9
6
9
6
,
8
7
8
4
S
N
R
a
f
t
e
r
f
i
l
t
e
r
i
n
g
(
d
B
)
5
,
8
9
8
5
,
8
5
9
5
5
,
8
3
4
9
5
,
8
1
8
4
5
,
8
0
6
9
S
N
R
P
S
D
b
e
f
o
r
e
f
i
l
t
e
r
i
n
g
(
d
B
)
5
,
7
3
4
1
5
,
7
3
4
1
5
,
7
3
4
1
5
,
7
3
4
1
5
,
7
3
4
1
S
N
R
P
S
D
a
f
t
e
r
f
i
l
t
e
r
i
n
g
(
d
B
)
2
5
,
2
2
2
2
6
,
2
3
4
2
7
,
0
0
9
8
2
7
,
6
3
6
2
8
,
1
6
2
3
T
ab
le
3
.
SNR
ca
lcu
latio
n
r
esu
lts
o
f
g
r
ass
h
o
p
p
er
s
o
u
n
d
s
r
ec
o
r
d
ed
f
o
r
2
0
s
ec
o
n
d
s
P
a
r
a
me
t
e
r
G
r
a
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s
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d
r
e
c
o
r
d
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n
g
f
o
r
2
0
s
e
c
o
n
d
s
d
o
m
i
n
a
n
t
f
r
e
q
u
e
n
c
y
r
a
n
g
e
5
8
1
4
H
z
-
9
0
1
6
H
z
F
i
l
t
e
r
o
r
d
e
r
4
5
6
7
8
S
N
R
b
e
f
o
r
e
f
i
l
t
e
r
i
n
g
(
d
B
)
6
,
8
5
0
7
6
,
7
5
2
4
6
,
6
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3
5
6
,
6
5
6
5
6
,
6
3
2
3
S
N
R
a
f
t
e
r
f
i
l
t
e
r
i
n
g
(
d
B
)
5
,
6
6
1
6
5
,
5
8
6
5
5
,
5
4
2
5
,
5
1
4
7
5
,
4
9
7
1
S
N
R
P
S
D
b
e
f
o
r
e
f
i
l
t
e
r
i
n
g
(
d
B
)
5
,
4
2
5
5
,
4
2
5
5
,
4
2
5
5
,
4
2
5
5
,
4
2
5
S
N
R
P
S
D
a
f
t
e
r
f
i
l
t
e
r
i
n
g
(
d
B
)
2
5
,
1
1
6
1
2
6
,
3
8
6
7
2
7
,
3
1
1
6
2
8
,
0
2
2
7
2
8
,
5
9
8
5
T
ab
le
4
.
SNR
ca
lcu
latio
n
r
esu
lts
o
f
g
r
ass
h
o
p
p
er
s
o
u
n
d
s
r
ec
o
r
d
ed
f
o
r
2
5
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o
n
d
s
P
a
r
a
me
t
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r
G
r
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o
r
d
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n
g
f
o
r
2
5
s
e
c
o
n
d
s
d
o
m
i
n
a
n
t
f
r
e
q
u
e
n
c
y
r
a
n
g
e
5
8
3
6
H
z
-
9
0
1
6
H
z
F
i
l
t
e
r
o
r
d
e
r
4
5
6
7
8
S
N
R
b
e
f
o
r
e
f
i
l
t
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i
n
g
(
d
B
)
6
,
9
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7
1
6
,
7
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8
6
6
,
7
3
4
6
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6
9
5
1
6
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(
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5
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7
1
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5
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,
6
3
2
8
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4
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5
5
6
1
5
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5
3
8
4
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6
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3
S
N
R
P
S
D
a
f
t
e
r
f
i
l
t
e
r
i
n
g
(
d
B
)
2
4
,
9
6
9
3
2
6
,
2
6
8
1
2
7
,
2
0
2
7
2
7
,
9
1
5
8
2
8
,
4
9
1
6
Fig
u
r
e
9
s
h
o
ws
th
e
PS
D
-
b
ased
SNR
v
alu
es
af
ter
f
ilter
i
n
g
f
o
r
v
ar
io
u
s
r
ec
o
r
d
in
g
d
u
r
atio
n
s
.
A
co
n
s
is
ten
t
im
p
r
o
v
em
e
n
t
tr
en
d
is
o
b
s
er
v
ed
ac
r
o
s
s
all
d
u
r
at
io
n
s
,
in
d
icatin
g
th
at
th
e
p
r
o
p
o
s
ed
f
ilter
in
g
an
d
s
p
ec
tr
al
an
aly
s
is
m
eth
o
d
r
em
ain
s
s
tab
le
an
d
r
eliab
le
ev
e
n
with
d
if
f
er
en
t
s
ig
n
al
len
g
th
s
.
Fig
u
r
e
1
0
co
m
p
a
r
es
PSD
-
b
ased
SNR
v
alu
es
b
ef
o
r
e
an
d
af
ter
f
ilter
in
g
f
o
r
a
2
0
-
s
ec
o
n
d
r
ec
o
r
d
in
g
.
T
h
e
s
u
b
s
tan
tial
in
cr
ea
s
e
in
SNR
af
ter
f
ilter
in
g
c
o
n
f
ir
m
s
th
e
ef
f
ec
tiv
en
ess
o
f
th
e
B
u
tter
wo
r
th
b
an
d
p
ass
f
ilter
in
e
n
h
an
ci
n
g
g
r
ass
h
o
p
p
er
ac
o
u
s
tic
s
ig
n
atu
r
es a
n
d
s
u
p
p
r
ess
in
g
en
v
ir
o
n
m
e
n
tal
n
o
is
e
u
n
d
er
r
ea
lis
tic
ag
r
icu
ltu
r
al
co
n
d
itio
n
s
.
B
ased
o
n
th
e
ta
b
le
an
d
g
r
ap
h
ab
o
v
e
,
s
ev
er
al
t
h
in
g
s
th
at
ca
n
b
e
d
is
cu
s
s
ed
ar
e
as
f
o
llo
ws.
Fig
u
r
es
2
an
d
3
p
r
o
v
id
e
a
n
in
itial
d
e
p
ictio
n
o
f
th
e
g
r
ass
h
o
p
p
e
r
ac
o
u
s
tic
s
ig
n
al
ch
ar
ac
ter
is
tics
u
n
d
e
r
r
ea
l
f
ield
co
n
d
itio
n
s
p
r
io
r
to
f
ilter
in
g
.
T
h
e
p
r
o
n
o
u
n
ce
d
am
p
litu
d
e
f
lu
ctu
atio
n
s
an
d
s
tr
o
n
g
n
o
is
e
c
o
n
tam
in
ati
o
n
o
b
s
er
v
ed
in
th
e
tim
e
-
d
o
m
ain
wav
ef
o
r
m
s
ar
e
c
o
n
s
is
ten
t
with
th
e
r
elati
v
ely
l
o
w
in
itial
SN
R
v
alu
es
r
ep
o
r
ted
in
T
ab
le
1
.
T
h
ese
r
esu
lts
in
d
icate
th
at
t
h
e
r
aw
r
e
co
r
d
in
g
s
ar
e
d
o
m
in
ate
d
b
y
e
n
v
ir
o
n
m
e
n
tal
n
o
is
e,
th
er
eb
y
j
u
s
tify
in
g
t
h
e
n
ee
d
f
o
r
s
u
b
s
eq
u
en
t sig
n
al
p
r
e
p
r
o
ce
s
s
in
g
an
d
f
ilter
in
g
s
tag
es.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
d
o
n
esian
J
E
lec
E
n
g
&
C
o
m
p
Sci
I
SS
N:
2502
-
4
7
5
2
Gra
s
s
h
o
p
p
er so
u
n
d
a
c
o
u
s
tic
s
ig
n
a
l a
n
a
lysi
s
u
s
in
g
fft a
n
d
B
u
tter
w
o
r
th
filt
er
(
K
h
a
ir
u
n
n
is
a
)
715
Fig
u
r
e
8
.
SNR
B
ef
o
r
e
an
d
Af
ter
F
ilter
in
g
(
r
ec
o
r
d
in
g
d
u
r
atio
n
f
o
r
1
0
s
ec
o
n
d
s
)
Fig
u
r
e
9
.
SNR
with
PS
D
af
ter
f
ilter
in
g
f
o
r
v
ar
io
u
s
r
ec
o
r
d
in
g
d
u
r
atio
n
T
h
e
f
r
eq
u
en
cy
s
p
ec
tr
u
m
an
d
s
p
ec
tr
o
g
r
am
p
r
esen
ted
in
F
ig
u
r
e
4
illu
s
tr
ate
th
at
s
ig
n
al
en
er
g
y
is
d
is
tr
ib
u
ted
ac
r
o
s
s
a
wid
e
f
r
eq
u
en
cy
b
a
n
d
b
e
f
o
r
e
f
ilter
in
g
.
T
h
is
o
b
s
er
v
atio
n
is
q
u
an
titativ
e
ly
s
u
p
p
o
r
ted
b
y
th
e
FF
T
r
esu
lts
s
u
m
m
ar
ized
in
T
ab
le
2
,
w
h
ich
id
e
n
tify
d
o
m
in
an
t
f
r
eq
u
en
cy
p
ea
k
s
with
in
th
e
r
an
g
e
o
f
ap
p
r
o
x
im
ately
5
.
8
–
9
k
Hz.
T
h
e
ag
r
ee
m
en
t b
etwe
en
th
e
s
p
ec
tr
al
v
is
u
aliza
tio
n
an
d
th
e
n
u
m
e
r
ical
FF
T
o
u
tco
m
es
r
ein
f
o
r
ce
s
th
e
v
alid
ity
o
f
s
elec
tin
g
th
is
f
r
eq
u
e
n
cy
b
an
d
as th
e
tar
g
et
r
an
g
e
f
o
r
g
r
ass
h
o
p
p
er
a
co
u
s
tic
an
aly
s
is
.
Fig
u
r
e
5
d
em
o
n
s
tr
ates
th
e
ef
f
ec
ts
o
f
B
u
tter
wo
r
th
b
an
d
p
ass
f
ilter
in
g
an
d
p
a
r
am
eter
s
elec
ti
o
n
o
n
th
e
g
r
ass
h
o
p
p
er
ac
o
u
s
tic
s
ig
n
al.
T
h
e
v
is
u
al
co
m
p
ar
is
o
n
b
et
wee
n
th
e
p
r
e
-
f
ilter
ed
a
n
d
p
o
s
t
-
f
ilter
ed
s
ig
n
als,
to
g
eth
er
with
th
e
ex
tr
ac
ted
p
a
r
am
eter
s
ettin
g
s
,
is
d
ir
ec
tly
r
e
f
lecte
d
in
th
e
SNR
v
ar
iatio
n
s
r
ep
o
r
ted
in
T
a
b
le
3
.
As
s
h
o
wn
in
th
e
tab
le,
i
n
cr
ea
s
in
g
th
e
f
ilter
o
r
d
er
lead
s
to
i
m
p
r
o
v
e
d
n
o
is
e
atten
u
atio
n
,
alb
eit
at
th
e
co
s
t
o
f
h
ig
h
er
c
o
m
p
u
tatio
n
al
co
m
p
lex
ity
.
T
h
is
co
n
s
is
ten
cy
b
etwe
e
n
v
is
u
al
ev
id
en
ce
an
d
n
u
m
e
r
ical
r
esu
lts
h
ig
h
lig
h
ts
th
e
s
y
s
tem
atic
b
eh
av
io
r
o
f
th
e
p
r
o
p
o
s
ed
f
ilter
in
g
a
p
p
r
o
ac
h
.
Fig
u
r
es
7
a
n
d
8
em
p
h
asize
th
e
co
n
tr
asti
n
g
b
eh
a
v
io
r
o
f
tim
e
-
d
o
m
ain
SNR
an
d
PS
D
-
b
ased
SNR
af
ter
f
ilter
in
g
.
W
h
ile
Fig
u
r
e
8
s
h
o
ws
a
s
lig
h
t
d
ec
r
ea
s
e
in
d
ir
ec
t
S
NR
,
T
ab
le
4
r
e
v
ea
ls
a
s
u
b
s
tan
tial
im
p
r
o
v
em
e
n
t
in
PSD
-
b
ased
SN
R
v
alu
es.
T
h
is
d
is
cr
ep
an
cy
co
n
f
ir
m
s
th
at
ti
m
e
-
d
o
m
ain
SNR
alo
n
e
is
in
s
u
f
f
icien
t
to
r
ep
r
esen
t
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
5
0
2
-
4
7
5
2
I
n
d
o
n
esian
J
E
lec
E
n
g
&
C
o
m
p
Sci
,
Vo
l.
42
,
No
.
3
,
J
u
n
e
20
26
:
7
0
8
-
7
2
0
716
s
p
ec
tr
al
clar
ity
,
wh
er
ea
s
PS
D
-
b
ased
m
etr
ics
m
o
r
e
ac
c
u
r
ately
ca
p
tu
r
e
en
e
r
g
y
c
o
n
ce
n
tr
atio
n
with
in
th
e
b
io
lo
g
ically
r
ele
v
an
t f
r
e
q
u
en
c
y
b
an
d
.
Fig
u
r
es
9
an
d
1
0
illu
s
tr
ate
th
e
co
n
s
is
ten
cy
o
f
PS
D
-
b
as
ed
SNR
im
p
r
o
v
em
en
t
ac
r
o
s
s
d
if
f
er
en
t
r
ec
o
r
d
in
g
d
u
r
atio
n
s
.
T
h
is
tr
e
n
d
is
co
n
s
is
ten
t
with
th
e
q
u
an
t
itativ
e
r
esu
lts
p
r
esen
ted
in
T
a
b
le
4
,
wh
ich
s
h
o
w
o
n
ly
m
in
o
r
v
a
r
iatio
n
s
in
PS
D
-
b
ased
SN
R
f
o
r
r
ec
o
r
d
in
g
d
u
r
atio
n
s
r
an
g
i
n
g
f
r
o
m
1
0
to
2
5
s
ec
o
n
d
s
.
T
h
ese
f
in
d
in
g
s
s
u
g
g
est
th
at
th
e
p
r
o
p
o
s
ed
m
eth
o
d
is
r
o
b
u
s
t
to
v
a
r
iatio
n
s
in
s
ig
n
al
len
g
th
an
d
r
em
ain
s
r
eliab
le
f
o
r
r
ea
l
-
tim
e
ac
o
u
s
tic
m
o
n
ito
r
in
g
ap
p
licatio
n
s
.
Fig
u
r
e
1
0
.
SNR
with
PS
D
co
m
p
ar
is
o
n
b
e
f
o
r
e
a
n
d
af
te
r
f
ilter
in
g
(
r
ec
o
r
d
i
n
g
d
u
r
atio
n
f
o
r
2
0
s
ec
o
n
d
s
)
3
.
1
.
F
ilte
r
ef
f
ec
t
iv
eness
T
o
ev
alu
ate
th
e
ef
f
ec
tiv
en
es
s
o
f
th
e
f
ilter
in
g
p
r
o
ce
s
s
,
th
e
SNR
was
an
aly
ze
d
b
ef
o
r
e
an
d
a
f
ter
ap
p
ly
in
g
th
e
b
an
d
p
ass
f
ilter
.
I
n
ad
d
itio
n
to
th
e
co
n
v
en
tio
n
al
tim
e
-
d
o
m
ain
SNR
ca
lcu
latio
n
,
a
PS
D
-
b
ased
SN
R
an
aly
s
is
u
s
in
g
th
e
W
elch
m
et
h
o
d
was
also
p
er
f
o
r
m
ed
to
p
r
o
v
id
e
a
m
o
r
e
co
m
p
r
eh
e
n
s
iv
e
ass
es
s
m
en
t
o
f
th
e
f
ilter
'
s
p
er
f
o
r
m
a
n
ce
in
is
o
latin
g
th
e
d
o
m
in
an
t f
r
eq
u
e
n
cy
c
o
m
p
o
n
en
ts
o
f
th
e
g
r
ass
h
o
p
p
er
s
o
u
n
d
:
−
T
h
e
SNR
b
ef
o
r
e
th
e
f
ilter
is
o
n
ly
ar
o
u
n
d
6
–
7
d
B
,
in
d
icatin
g
th
at
th
e
in
itial
r
ec
o
r
d
in
g
q
u
ality
is
s
ti
ll
lo
w
with
a
lo
t o
f
en
v
ir
o
n
m
en
tal
n
o
is
e.
−
T
h
e
g
en
e
r
al
SNR
af
ter
th
e
f
ilter
is
ac
tu
ally
s
lig
h
tly
lo
wer
(
5
.
5
–
5
.
9
d
B
)
.
T
h
is
is
b
ec
au
s
e
th
e
b
an
d
p
ass
f
ilter
also
r
em
o
v
es so
m
e
o
f
th
e
o
r
i
g
in
al
s
ig
n
al
en
er
g
y
o
u
ts
id
e
th
e
t
ar
g
et
r
an
g
e
,
r
esu
ltin
g
in
a
n
o
ti
ce
ab
le
d
ec
r
ea
s
e
in
th
e
d
ir
ec
t r
atio
.
−
Ho
wev
er
,
th
e
PS
D
-
b
ased
SNR
(
u
s
in
g
th
e
W
elch
ap
p
r
o
x
im
atio
n
)
s
h
o
ws d
if
f
er
en
t r
esu
lts
:
−
B
ef
o
r
e
th
e
f
ilter
: a
r
o
u
n
d
5
.
4
–
5
.
7
d
B
.
−
Af
ter
th
e
f
ilter
: a
d
r
asti
c
in
cr
e
ase
to
2
5
–
2
8
d
B
.
−
T
h
is
in
cr
ea
s
e
o
f
m
o
r
e
th
an
2
0
d
B
in
d
icate
s
th
at
th
e
f
ilter
i
s
v
er
y
ef
f
ec
tiv
e
at
r
ed
u
ci
n
g
en
er
g
y
o
u
ts
id
e
th
e
g
r
ass
h
o
p
p
e
r
'
s
d
o
m
in
an
t f
r
e
q
u
en
cy
b
an
d
(
~5
.
8
–
9
k
Hz)
.
3
.
2
.
E
f
f
ec
t
o
f
f
ilte
r
o
rder
T
o
ev
alu
ate
th
e
ef
f
ec
t
o
f
f
ilte
r
d
esig
n
o
n
n
o
is
e
r
ed
u
ctio
n
p
er
f
o
r
m
a
n
ce
,
th
e
ef
f
ec
t
o
f
b
an
d
p
ass
f
ilter
o
r
d
er
o
n
th
e
SNR
was
an
aly
ze
d
.
Fil
ter
o
r
d
er
d
eter
m
in
es
t
h
e
s
h
ar
p
n
ess
o
f
th
e
f
r
eq
u
en
c
y
r
esp
o
n
s
e
an
d
th
e
ab
ilit
y
to
s
u
p
p
r
ess
u
n
wa
n
ted
f
r
eq
u
e
n
cy
c
o
m
p
o
n
en
ts
.
T
h
e
PS
D
-
b
ased
SNR
v
alu
es
o
b
tain
ed
f
r
o
m
d
i
f
f
er
en
t
f
ilter
o
r
d
er
s
wer
e
c
o
m
p
ar
e
d
to
ass
es
s
im
p
r
o
v
em
en
ts
in
th
e
q
u
ality
o
f
th
e
r
ec
o
r
d
ed
g
r
ass
h
o
p
p
er
s
o
u
n
d
.
−
C
o
n
s
is
ten
t tr
en
d
ac
r
o
s
s
all
r
ec
o
r
d
in
g
d
u
r
ati
o
n
s
:
As th
e
f
ilter
o
r
d
er
i
n
cr
ea
s
es (
f
r
o
m
4
t
o
8
)
,
th
e
PS
D
-
b
ased
SNR
af
ter
f
ilter
in
g
im
p
r
o
v
es
E
x
am
p
le:
2
0
-
s
ec
o
n
d
d
u
r
atio
n
:
4
th
-
o
r
d
e
r
: 2
5
.
1
1
d
B
an
d
8
th
-
o
r
d
er
: 2
8
.
5
9
d
B
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
d
o
n
esian
J
E
lec
E
n
g
&
C
o
m
p
Sci
I
SS
N:
2502
-
4
7
5
2
Gra
s
s
h
o
p
p
er so
u
n
d
a
c
o
u
s
tic
s
ig
n
a
l a
n
a
lysi
s
u
s
in
g
fft a
n
d
B
u
tter
w
o
r
th
filt
er
(
K
h
a
ir
u
n
n
is
a
)
717
−
T
h
e
SNR
-
b
ased
PS
D
in
cr
ea
s
e
s
b
y
ap
p
r
o
x
im
ately
0
.
7
–
1
d
B
with
ea
ch
in
cr
em
en
t i
n
f
ilter
o
r
d
er
−
I
n
o
th
er
w
o
r
d
s
,
h
ig
h
er
-
o
r
d
er
f
i
lter
s
y
ield
s
teep
er
o
u
t
-
of
-
b
an
d
atten
u
atio
n
,
r
esu
ltin
g
i
n
m
o
r
e
ef
f
ec
tiv
e
n
o
is
e
s
u
p
p
r
ess
io
n
3
.
3
.
E
f
f
ec
t
o
f
re
c
o
rding
du
ra
t
io
n
T
o
ass
es
s
th
e
ef
f
ec
t
o
f
r
ec
o
r
d
in
g
d
u
r
atio
n
o
n
f
ilter
in
g
p
er
f
o
r
m
a
n
ce
,
th
e
PS
D
-
b
ased
SNR
wa
s
an
aly
ze
d
u
s
in
g
r
ec
o
r
d
in
g
s
o
f
d
if
f
er
en
t
len
g
t
h
s
.
L
o
n
g
er
r
e
co
r
d
in
g
s
g
e
n
er
ally
p
r
o
v
id
e
m
o
r
e
s
tab
le
s
p
ec
tr
al
esti
m
ates,
lead
in
g
to
m
o
r
e
r
eliab
le
SNR
m
ea
s
u
r
em
en
ts
an
d
f
ilter
p
er
f
o
r
m
an
ce
ev
al
u
atio
n
:
−
T
h
e
SNR
-
b
ased
PS
D
af
ter
f
ilt
er
in
g
ten
d
s
to
in
cr
ea
s
e
s
lig
h
tly
with
lo
n
g
er
r
ec
o
r
d
in
g
d
u
r
ati
o
n
s
:
10
-
s
ec
o
n
d
d
u
r
atio
n
: ~
2
7
.
9
d
B
(
8
th
o
r
d
e
r
)
an
d
25
-
s
ec
o
n
d
d
u
r
atio
n
: ~
2
8
.
5
d
B
(
8
th
o
r
d
er
)
−
T
h
e
d
if
f
e
r
en
ce
is
r
elativ
ely
s
m
all
(
~0
.
5
–
0
.
6
d
B
)
,
b
u
t
c
o
n
s
is
ten
t.
−
T
h
is
o
cc
u
r
s
b
ec
au
s
e
lo
n
g
er
r
e
co
r
d
in
g
s
p
r
o
v
i
d
e
m
o
r
e
s
tab
le
PS
D
esti
m
ate
s
(
m
o
r
e
ev
en
a
v
e
r
ag
e
n
o
is
e)
.
T
h
e
an
aly
s
is
r
esu
lts
s
h
o
w
th
at
ap
p
ly
in
g
a
B
u
tter
wo
r
th
b
a
n
d
p
ass
f
ilter
s
ig
n
if
ican
tly
im
p
r
o
v
es
th
e
q
u
ality
o
f
th
e
g
r
ass
h
o
p
p
er
ca
ll
s
ig
n
al.
T
h
e
PS
D
-
b
ased
SNR
v
alu
e
in
c
r
ea
s
ed
s
h
ar
p
ly
f
r
o
m
ar
o
u
n
d
5
d
B
i
n
th
e
o
r
ig
in
al
s
ig
n
al
to
2
5
–
2
8
d
B
a
f
ter
f
ilter
in
g
.
T
h
is
in
cr
ea
s
e
o
f
m
o
r
e
th
a
n
2
0
d
B
in
d
icate
s
th
a
t
th
e
f
ilter
is
ca
p
a
b
le
o
f
r
ed
u
cin
g
n
o
is
e
en
er
g
y
o
u
ts
id
e
th
e
d
o
m
in
a
n
t
f
r
e
q
u
en
c
y
b
an
d
o
f
th
e
g
r
ass
h
o
p
p
er
(
±
5
.8
–
9
k
Hz)
,
th
u
s
clar
if
y
in
g
t
h
e
ch
ar
ac
te
r
is
tics
o
f
th
e
tar
g
et
s
ig
n
al.
I
n
c
o
n
tr
ast,
th
e
SNR
ca
lcu
lated
u
s
in
g
a
s
im
p
ler
m
et
h
o
d
(
d
ir
ec
t
co
m
p
ar
is
o
n
b
etwe
en
th
e
o
r
ig
in
al
s
ig
n
al
an
d
th
e
f
ilt
er
ed
r
esu
lt)
s
h
o
wed
a
s
lig
h
t
d
ec
r
ea
s
e.
T
h
is
o
cc
u
r
s
b
ec
au
s
e
th
e
f
ilter
n
o
t
o
n
ly
r
e
d
u
ce
s
n
o
is
e
b
u
t
also
r
em
o
v
es
s
o
m
e
s
ig
n
al
en
er
g
y
o
u
ts
id
e
t
h
e
s
p
ec
if
ied
b
an
d
,
m
ak
in
g
th
e
PS
D
m
eth
o
d
a
m
o
r
e
r
ep
r
esen
tativ
e
way
to
ass
ess
f
ilter
in
g
s
u
cc
ess
.
Fu
r
th
er
m
o
r
e
,
th
er
e
is
a
p
o
s
itiv
e
co
r
r
elatio
n
b
etwe
en
f
ilter
o
r
d
er
an
d
PS
D
SN
R
v
alu
e.
I
n
cr
ea
s
in
g
th
e
o
r
d
er
f
r
o
m
4
to
8
r
esu
lts
in
an
SNR
im
p
r
o
v
em
en
t
o
f
ap
p
r
o
x
im
ately
0
.
7
–
1
d
B
p
er
o
r
d
er
s
tep
.
T
h
is
in
d
icate
s
th
at
h
ig
h
er
-
o
r
d
er
f
ilter
s
h
av
e
a
s
h
ar
p
er
f
r
eq
u
e
n
cy
r
esp
o
n
s
e
in
atten
u
atin
g
o
u
t
-
of
-
b
a
n
d
s
ig
n
als,
th
u
s
m
o
r
e
ef
f
ec
tiv
ely
s
u
p
p
r
ess
in
g
n
o
is
e.
Ho
wev
er
,
s
elec
tin
g
th
e
f
ilter
o
r
d
er
r
e
q
u
ir
es
co
n
s
id
er
in
g
th
e
tr
ad
e
-
o
f
f
b
etwe
en
p
er
f
o
r
m
an
ce
an
d
co
m
p
lex
ity
,
with
an
o
r
d
e
r
o
f
6
–
8
co
n
s
id
er
e
d
o
p
tim
al.
R
ec
o
r
d
in
g
d
u
r
atio
n
also
af
f
e
cts
th
e
s
tab
ilit
y
o
f
th
e
an
aly
s
is
r
esu
lts
.
T
h
e
SNR
o
f
th
e
PS
D
af
ter
f
ilter
in
g
ten
d
s
to
in
cr
ea
s
e
s
lig
h
tly
with
lo
n
g
e
r
r
ec
o
r
d
in
g
s
,
with
a
d
if
f
er
en
ce
o
f
ap
p
r
o
x
im
ately
0
.
5
–
0
.
6
d
B
b
etwe
en
1
0
-
s
ec
o
n
d
an
d
2
5
-
s
ec
o
n
d
r
ec
o
r
d
in
g
s
.
T
h
is
ca
n
b
e
e
x
p
lain
ed
b
y
th
e
PS
D
esti
m
atio
n
p
r
o
ce
s
s
b
ec
o
m
in
g
m
o
r
e
s
tab
le
with
a
lar
g
er
s
am
p
le
s
ize,
r
esu
ltin
g
in
m
o
r
e
ev
e
n
n
o
i
s
e
f
lu
ctu
ati
o
n
s
.
Ho
wev
er
,
th
is
in
cr
ea
s
e
is
r
elativ
ely
s
m
all,
s
o
ev
en
a
1
0
-
s
ec
o
n
d
r
ec
o
r
d
i
n
g
is
s
u
f
f
icien
t
f
o
r
an
aly
s
is
p
u
r
p
o
s
es,
wh
ile
lo
n
g
er
r
ec
o
r
d
in
g
s
ar
e
u
s
ef
u
l
f
o
r
i
n
cr
e
asin
g
th
e
r
eliab
ilit
y
o
f
th
e
r
esu
lts
.
Ov
er
all,
th
e
c
o
m
b
in
ati
o
n
o
f
F
FT,
B
u
tter
wo
r
th
b
an
d
p
ass
f
ilter
,
an
d
PS
D
an
aly
s
is
p
r
o
v
ed
e
f
f
ec
tiv
e
in
en
h
an
cin
g
th
e
f
r
eq
u
e
n
cy
s
ig
n
atu
r
e
o
f
g
r
ass
h
o
p
p
er
ca
lls
wh
ile
s
u
p
p
r
ess
in
g
en
v
ir
o
n
m
en
tal
n
o
is
e.
T
h
ese
f
in
d
in
g
s
c
o
n
f
ir
m
th
at
th
e
p
r
o
p
o
s
ed
m
eth
o
d
ca
n
b
e
u
s
ed
as
a
f
ir
s
t
s
tep
in
a
s
ig
n
al
a
n
aly
s
is
-
b
ased
p
lan
t
p
est
ac
o
u
s
tic
d
etec
tio
n
s
y
s
tem
.
T
h
e
d
ec
r
ea
s
e
in
d
ir
ec
t
SNR
af
ter
f
ilter
in
g
o
cc
u
r
s
b
ec
au
s
e
th
e
b
an
d
p
ass
f
ilter
r
em
o
v
es n
o
t o
n
ly
n
o
is
e
co
m
p
o
n
en
ts
b
u
t a
ls
o
p
o
r
tio
n
s
o
f
s
ig
n
al
en
er
g
y
o
u
ts
id
e
th
e
d
ef
i
n
ed
f
r
eq
u
en
cy
b
a
n
d
.
As
a
r
esu
lt,
d
ir
ec
t
SN
R
alo
n
e
i
s
les
s
r
ep
r
esen
tativ
e
o
f
s
p
ec
tr
al
clar
ity
.
I
n
co
n
tr
ast,
PS
D
-
b
ased
SNR
m
o
r
e
ac
cu
r
ately
r
ef
lects
en
er
g
y
co
n
ce
n
tr
atio
n
with
in
th
e
b
io
lo
g
ic
ally
r
elev
an
t
f
r
eq
u
e
n
cy
r
an
g
e,
wh
ich
ex
p
lain
s
th
e
s
ig
n
if
ican
t im
p
r
o
v
em
en
t o
b
s
er
v
ed
af
ter
f
ilter
in
g
.
Hig
h
er
-
o
r
d
er
f
ilter
s
p
r
o
v
i
d
e
s
t
ee
p
er
o
u
t
-
of
-
b
an
d
atten
u
atio
n
b
u
t
also
in
cr
ea
s
e
co
m
p
u
tatio
n
al
co
m
p
lex
ity
an
d
p
h
ase
d
ela
y
.
Fo
r
r
ea
l
-
tim
e
em
b
ed
d
ed
im
p
l
em
en
tatio
n
s
,
f
ilter
o
r
d
e
r
s
b
etwe
en
6
an
d
8
o
f
f
e
r
a
p
r
ac
tical
tr
ad
e
-
o
f
f
b
etwe
en
n
o
is
e
s
u
p
p
r
ess
io
n
p
e
r
f
o
r
m
an
ce
an
d
p
r
o
ce
s
s
in
g
ef
f
icien
cy
.
Alt
h
o
u
g
h
t
h
e
ex
p
er
im
en
ts
wer
e
co
n
d
u
cte
d
u
n
d
er
c
o
n
tr
o
lled
f
ield
co
n
d
itio
n
s
,
th
e
id
en
tifie
d
f
r
eq
u
en
cy
r
an
g
e
(
≈
5
.
8
–
9
k
Hz
)
alig
n
s
with
g
r
ass
h
o
p
p
e
r
ac
o
u
s
tic
ch
ar
ac
ter
is
tics
r
ep
o
r
t
ed
in
p
r
ev
io
u
s
s
tu
d
ies,
s
u
g
g
esti
n
g
r
ea
s
o
n
a
b
le
g
en
er
aliza
b
ilit
y
to
s
im
ilar
ag
r
i
cu
ltu
r
a
l e
n
v
ir
o
n
m
en
ts
.
W
h
ile
th
e
d
ataset
s
ize
is
lim
ited
,
r
ep
ea
ted
m
ea
s
u
r
em
en
ts
ac
r
o
s
s
m
u
ltip
le
r
ec
o
r
d
i
n
g
d
u
r
atio
n
s
an
d
f
ilter
o
r
d
e
r
s
p
r
o
v
id
e
in
d
ir
ec
t
v
alid
atio
n
o
f
th
e
p
r
o
p
o
s
ed
m
eth
o
d
.
Fu
tu
r
e
wo
r
k
will
f
o
c
u
s
o
n
th
e
u
s
e
o
f
m
u
lti
-
lo
ca
tio
n
a
n
d
m
u
lti
-
s
p
ec
ies
d
atasets
to
f
u
r
th
er
ass
ess
r
o
b
u
s
tn
ess
u
n
d
er
d
iv
er
s
e
en
v
ir
o
n
m
en
tal
c
o
n
d
itio
n
s
.
4.
CO
NCLU
SI
O
N
T
h
is
s
tu
d
y
aim
ed
to
in
v
esti
g
ate
th
e
ef
f
ec
tiv
en
ess
o
f
class
ical
s
ig
n
al
p
r
o
ce
s
s
in
g
tech
n
iq
u
es
f
o
r
en
h
an
cin
g
g
r
ass
h
o
p
p
er
ac
o
u
s
tic
s
ig
n
als
u
n
d
e
r
n
o
is
y
ag
r
icu
lt
u
r
al
f
ield
co
n
d
itio
n
s
.
T
h
e
r
esu
lts
d
em
o
n
s
tr
ate
th
at
th
is
o
b
jectiv
e
h
as
b
ee
n
s
u
cc
ess
f
u
lly
ac
h
iev
ed
th
r
o
u
g
h
th
e
co
m
b
in
ed
ap
p
licatio
n
o
f
B
u
tter
wo
r
th
b
an
d
p
ass
f
ilter
in
g
,
FF
T
,
an
d
PS
D
an
aly
s
is
.
T
h
e
ap
p
licatio
n
o
f
th
e
B
u
tter
wo
r
th
b
an
d
p
ass
f
ilter
s
ig
n
if
ican
t
ly
im
p
r
o
v
e
d
s
ig
n
al
q
u
ality
,
as
in
d
icate
d
b
y
an
i
n
cr
ea
s
e
in
PS
D
-
b
ased
SNR
f
r
o
m
ap
p
r
o
x
im
ately
5
d
B
to
2
5
–
2
8
d
B
.
Hig
h
er
f
ilter
o
r
d
e
r
s
r
esu
lted
in
s
tr
o
n
g
er
n
o
is
e
s
u
p
p
r
ess
io
n
,
with
f
ilt
er
o
r
d
er
s
b
etwe
en
6
an
d
8
p
r
o
v
id
in
g
an
o
p
tim
al
b
alan
ce
b
etwe
en
s
p
ec
tr
al
e
n
h
a
n
ce
m
en
t
a
n
d
c
o
m
p
u
tatio
n
al
ef
f
icien
cy
.
L
o
n
g
er
r
ec
o
r
d
in
g
d
u
r
atio
n
s
y
ield
e
d
m
o
r
e
s
tab
le
SNR
esti
m
ates,
al
th
o
u
g
h
th
eir
o
v
er
all
im
p
ac
t
r
e
m
ain
ed
r
elativ
ely
lim
ited
.
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