ENGG2310A (Spring 2015)
Suggested Answers
Assignment 3
Question 1
(a) Binary with unipolar signaling (signal amplitude take with 0 Volts or +A Volts), where A is a
positive integer.
Eb
Pb 106 Q
Eb
4.7645
As bit rate Rb=2.08106, =210-8 Eb=4.5410-7 J
Tutorial 1
Review of Signals and Systems
Yang Qianmei
[email protected]
SHB 832
Outline
Basics of Signals
Linear Time-Invariant (LTI) Systems
Fourier Series
Fourier Transform
Basics of Signals
Signal is a function of time that conveys information about
Principles of Communication System
Tutorial 2
Liao Guocheng
[email protected]
SHB 825
1/15
Outline
Fourier Transform
Convolution
LTI System described by differential Equations
Energy Spectral Density
Power Spectral Density
2/15
Fourier Transform
Fourie
Principles of Communication System
Tutorial 5
Liao Guocheng
[email protected]
SHB 825
1/10
Outline
Answers to mid-term test
Superheterodyne receiver
Time Division Multiplexing
2/10
Answers to mid-term test
Q1:
(a)(b) Using revised version of g(t) and
THE CHINESE UNIVERSITY OF HONG KONG
ENGG2310-B: Principles of Communication Systems
Tutorial 4 Solution
Edited by SHAO Mingjie
October 4, 2015
SOLUTION 1
(a) In DSB-SC, we have s(t ) m(t ) c(t ) . The time-domain waveform of the
modulated signal is shown
ENGG 2310-B: Principles of Communication Systems
201415 Second Term
Midterm Examination
Time Limit: 55 minutes
October 15, 2014
Answer ANY TWO questions. No bonus will be given for answering all questions. State
which two questions you answer. If not sta
THE CHINESE UNIVERSITY OF HONG KONG
ENGG2310-B: Principles of Communication Systems
Tutorial 4
Edited by SHAO Mingjie
October 4, 2015
EXERCISE 1
Suppose that the message signal m(t ) Am cos 2 f mt is modulated by the carrier
c(t ) Ac cos 2 f ct via Double
Tutorial 7
Yang Qianmei
[email protected]
SHB 832
Outline
Digital Signal Detection
Example
Linear Block Codes
Hamming weight
Hamming distance
Digital Signal Detection
Digital Signal Detection
Want: to find si , i cfw_1, 2,., M such that
P ( si ri ) : P
Review of Signals and Systems
Assignment 1s Answers
The Principle of Communication
Tutorial 3
Cao Qi
[email protected]
SHB 727
Digital Communications
Review of Signals and Systems
Assignment 1s Answers
Outline
1
Review of Signals and Systems
2
Assignme
REVIEW
Problem Set 2
The Principle of Communication
Tutorial 6
Cao Qi
[email protected]
SHB 727
REVIEW
Problem Set 2
Outline
1
REVIEW
PCM
TDM
2
Problem Set 2
Problem 2-1
Problem 2-3
Problem 2-8
REVIEW
Problem Set 2
PCM
Ts /n
Ts
L = 8 and n = log2 L = 3
ENGG2310 Principles of Communication Systems (Spring 2015)
Test 1 Suggested Solution
Question 1
(a) The function a(t) can be written as a ( t ) = f1 ( t ) f 2 ( t ) f 3 ( t ) ,
where
4 | t |< 3
1 | t |< 2
2 | t |< 1
f1 (t ) =
, f 2 (t ) =
, f 3 (t ) =
ENGG2310A (Spring 2015)
Assignment 2
Suggested Answers
Question 1
(a)
(qe ) max
1 2Vmax
(
) 0.014Vmax
2 2 L
L 71.4
Choose L 27 128
number of bits per sample, n 7
(b)
Sampling rate f s 1.4 2 4.2kHz 11.76kHz
PCM bit rate R nf s 82.32kbit / s
Minimum
ENGG2310A (Spring 2015) Assignment #1
Suggested Solutions
Question 1
We learn from the diagram that T0 4 , then the exponential form of y (t) is
y (t)
n
Sn e
j 2 nt
T0
where
1
Sn
T0
T0
2
T
0
2
y (t)e
j 2 nt
T0
dt
j 2 nt
j 2 nt
j 2 nt
j 2 nt
0
1
2
1 1
Question 1
(a) L=128
1 2V p 1 2V p
= =
(qe ) MAX
The maximum tolerable error =
=
0.78125%V p
2 2 L 2 128
(b) The signal-to-quantization-noise ratio is calculated as
=
(dB) 20
=
log10 L 42.14dB
SNR
(c) Consider the full utilization of the system band
ENGG2310A (Fall 2016)
Assignment 1
Due: October 4, 2016
Question 1
(a) Determine the Fourier Series of the following periodic signal a(t) in exponential
form:
a(t)
A
-5
-4
-3
-2
-1
0
1
2
3
4
5
time (t)
-A
(a) When the signal a(t) is applied to the input o
ENGG2310A (Fall 2016) Problem Set #1 Suggestion Answers
Problem 1-1
c e
x(t )
(1) Let
k
1
T0
ck
and:
T0
0
jk 0 t
x(t )e jk0t dt
2
T0
0
and
k
1 T0 2 jk0t
Ae
dt
T0 0
T0 2
A
A
e jk0t
(e jk0 T0 2 1)
0
- jk0T0
jk0T0
A
A
(1 e jk )
[1 ( 1) k ]
jk 2
jk 2
o
ENGG2310A (Fall 2016)
Problem 1-1
Consider the periodic square wave x(t) as shown below. Determine the complex exponential
Fourier series of x(t).
x(t)
A
-To -To/2
0
To/2
To
t
2To
Hence, determine the complex exponential Fourier series of y(t).
y(t)
A
-To
ENGG 2310-B: Principles of Communication Systems
201516 First Term
Assignment 1
Instructor: Wing-Kin Ma
Due: 5:30pm, October 8, 2015
Problem 1
(a) (15%) Consider the signal shown in Figure 1. It can be expressed as
t, 0 < t < 1
g(t) =
0, otherwise.
Show b
T HE C HINESE U NIVERSITY OF H ONG KONG
ENGG2310B Tutorial 1 Suggested Solutions
Edited by Lufei, GAO
September 16, 2015
1 P ROBLEM I
1.1 BY INTEGRATION
Z
ZT
A
A
(e j 2 f T 1) =
e j f T (e j f T e j f T )
j
2
f
j
2
f
0
sin( f T ) j f T
A
jf T
=
e
(2 j sin
T HE C HINESE U NIVERSITY OF H ONG KONG
ENGG2310B Tutorial 1
Edited by Lufei, GAO
September 16, 2015
1 P ROBLEM I
Solve the Fourier transform of
g (t ) =
A, 0 < t < T
0, otherwise
by direct integration. Verify that the result is the same as that by proper
Digital Signal Detection
At the receiving end of the digital communication system:
AWGN
n(t)
si(t)
Sampled
at t=kTs
r(t)
Receive
Decision
y(t) y(kTs) device
filter
1 if y(kTs)>
0 if y(kTs)<
Polar NRZ Signaling
s1 (t ) = + A
si (t ) =
s2 (t ) = A
0t T
fo
ERG2310A
Principles of Communication systems
PartI:ReviewonSignals&
Systems,Probability
ERG2310A-I
p. I-1
Part I: Review on Signals & Systems,
and Probability
Outline:
Basics of Signals
Linear Time-Invariant (LTI) Systems
Fourier Series
Fourier Transform
Angle Modulation
A continuous-wave (CW) sinusoidal signal can be varied by changing
its amplitude and its phase angle.
s (t ) = A(t ) cos[ c t + (t )]
To carry a message signal x(t):
Amplitude modulation:
Keep (t) constant and varies A(t) proportionally t
Noises
Noises : random fluctuations of power in systems
Corrupt the signal waveform
Degrade the performance of communication systems
Sources of Noises: random wandering of free electrons in resistors
(thermal noise), random flow of charges in
semiconducto
ERG2310A
Principles of Communication systems
IntroductiontoElectronic
Communicationsystems
ERG2310A-Introduction
p. Intro-1
Introduction to Communication Systems
Information: Voice, data, image, video, music, etc.
Communication systems
Deliver or exchange
Probability and Random Variables
Concept of Probability:
When the outcome of an event is not always the same, probability is
the measure of the chance of obtaining a particular possible outcome
NA
N N
P( A) = lim
Where N is total number of event occurrenc
INTRODUCTION TO COMPLEX
NUMBER
ERG 2130A
Principle of Communication System
WHY COMPLEX NUMBER?
Can the following polynomial equation be
solved?
x2 + 1=0
For years, numbers such as the square root of
a negative eleven were called impossible
number.
Comple