... Digital communications I:
Modulation and Coding Course
Period 3 - 2007
Catharina Logothetis
Lecture 6
Lecture 6 10
The raised ... with ISI:
Binary-PAM, SRRQ pulse
Non-ideal channel and no noise
)(7.0)()( Tttth
c
−+=
δδ
Lecture 6 24
Example of eye pattern with ISI:
Binary-PAM, SRRQ pulse …
AWGN (Eb/N0=20 dB) and ISI
)(7.0)()( ... noise and no ISI)
Lecture 6 17
Example o...
... iEE
sii
s
s
ski
Ed
ki
Ed
2
2
min
,
=
≠
=
Digital Communications I:
Modulation and Coding Course
Term 3 - 2008
Catharina Logothetis
Lecture 5
Lecture 5 20
Eb/No figure of merit in digital
communications
SNR or ... noise vector are i.i.d
Gaussian random variables with zero-mean and
variance . The noise vector pdf is
The elements of observed vector are
independent Gaus...
... R
k
n
R
c
=
)(
cB
pfP =
Digital Communications I:
Modulation and Coding Course
Term 3 - 2008
Catharina Logothetis
Lecture 13
Lecture 13 20
Design example of coded systems …
Choose a modulation/ coding scheme ... Sample
Detect
C
h
a
n
n
e
l
Digital modulation
Digital demodulation
Lecture 13 29
Course summary – cont’d
In details, we studies:
1. Basic de...
... Digital Communications I:
Modulation and Coding Course
Period 3 - 2007
Catharina Logothetis
Lecture 10
Lecture 10 10
Effective code rate
Initialize the memory before encoding the ... bits
Lecture 10 2
Last time, we talked about:
Channel coding
Linear block codes
The error detection and correction capability
Encoding and decoding
Hamming codes
Cyclic codes
Lec...
...
jnj
n
tj
M
pp
j
n
P
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−
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⎟
⎠
⎞
⎜
⎜
⎝
⎛
≤
∑
)1(
1
jnj
n
tj
B
pp
j
n
j
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⎟
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⎠
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1
p
Digital Communications I:
Modulation and Coding Course
Period 3 - 2007
Catharina Logothetis
Lecture 9
Lecture 9 22
Linear ... error detection and correction codes
Lecture 9 7
Why using error correction coding?
Error performance vs. bandwidth
Power vs. bandwi...
... from the received
sequence
Digital Communications I:
Modulation and Coding Course
Period 3 - 2007
Catharina Logothetis
Lecture 12
Lecture 12 5
Soft and hard decision decoding
In hard decision: ... 6
Soft and hard decision decoding …
ML soft-decisions decoding rule:
Choose the path in the trellis with minimum
Euclidean distance from the received
sequence
ML hard-d...
... Modulation, Demodulation and
Coding Course
Period 3 - 2007
Catharina Logothetis
Lecture 11
Lecture 11 10
Trellis ... levels.
Decoding based on soft-bits, is called the
“soft-decision decoding”.
On AWGN channels, 2 dB and on fading
channels 6 dB gain are obtained by using
soft-decoding over hard-decoding.
Lecture ... only to two level) which are called “hard-
bits”.
Decoding...