Digital Signal Processing Reference
In-Depth Information
A
n
alog sign
a
l
Digit
a
l data: 10
1
10
1
1
0.5
0
0
-1
0
2
4
6
0
2
4
6
t-->
t-->
A
WGN Noi
s
e
A
WGN Noi
s
e
1
1
0.5
0.5
0
0
0
2
4
6
0
2
4
6
t-->
t-->
Noisy d(t) at Rx
N
o
isy v(t) at Rx
2
2
1
1
0
0
-1
0
2
4
6
0
2
4
6
t-->
t-->
Fig. 1.6
AWGN attacked digital and analog signal
hand of we want to convert a digital low pass filter into a high pass filter, we
can easily change the digital filter transfer function [H(z)] just by changing some
coefficients (
a
0
,
a
1
,
a
2
...
.,
b
0
,
b
1
,
b
2
,
...
.. ).
Where
a
1
z
−
1
a
2
z
−
2
a
0
+
+
+
...
..
H
(
z
)
=
b
0
+
b
1
z
−
1
+
b
2
z
−
2
+
...
..
Just taking the example of any multimedia audio player, we can get a clear
view of the system. When the graphic equalizer is set to a 'high treble' preset, the
entire system of reconstruction process responds as a highpass filter. Just at the
very next instance if anyone chose to listen 'high bass' music, the reconstruction
system responds like a lowpass filter. It's done only by dynamically change of
coefficients values.
4.
Aging:
Aging signifies growing older of the system. It is obviously less effective
in case of digital systems. In case of analog systems, the output may change after
a few years due to aging of the discrete analog components like diode. As time
goes, the cut-in voltage of the diode increases slowly and unsteadily. This causes
fluctuation in the system performance. In digital systems, the system error due
to the problem of aging is totally absent.
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