Digital Signal Processing Reference
In-Depth Information
10
10
0
0
−
10
−
10
−
20
−
20
−
30
−
30
−
40
−
40
−
50
−
50
−
60
−
60
−
70
−
70
−
80
−
80
0
.
5
1
.
0
1
.
5
2
.
0
2
.
5 3
.
0 3
.
5
4
.
0
0
0
.
5
1
.
0 1
.
5 2
.
0 2
.
5 3
.
0
3
.
5 4
.
0
0
F
(kHz)
F
(kHz)
(
a
)
(
b
)
10
10
0
0
−
10
−
10
−
20
−
20
−
30
−
30
−
40
−
40
−
50
−
50
−
60
−
60
−
70
−
70
−
80
−
80
0
0
.
5 1
.
0 1
.
5 2
.
0 2
.
5 3
.
0 3
.
5 4
.
0
0
0
.
5 1
.
0 1
.
5 2
.
0 2
.
5 3
.
0 3
.
5 4
.
0
F
(kHz)
F
(kHz)
(c)
(d)
FIG. 4.27
The white noise gain of the second-order cardioid with one distinct null, as a
function of frequency, for different values of
Δ
: (a)
Δ
= 1 cm, (b)
Δ
= 2 cm, (c)
Δ
= 3 cm,
and (d)
Δ
= 5 cm.
(
ω
)]
≈
256
294
(
ωτ
0
)
4
,
′
G
WN,2
[
h
(4.44)
from which we deduce that the white noise is amplified if
1/4
≈
1
.
04
.
294
256
ωτ
0
<
(4.45)
The directivity factor of the second-order cardioid with one distinct null
is
2
16
7
−
16
2
1
− e
2
ωτ
0
7
e
ωτ
0
/
2
′
G
DN,2
[
h
(
ω
)] =
,
(4.46)
D
DN,2
(
ω
)
where
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