and networks fundamentals Practical Part Tutorial 2 Chapter 3 Data amp computer communications Networks and Communication Department 1 Revision Networks and Communication Department ID: 662965
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Net 222: Communications and networks fundamentals (Practical Part)
Tutorial 2 : Chapter 3 Data & computer communications
Networks and Communication Department
1Slide2
Revision Networks and Communication Department
2Trigonometric FunctionsSlide3
Revision (Cont.)Networks and Communication Department
3Trigonometric FunctionsSlide4
Revision (Cont.)Networks and Communication Department
4Slide5
Revision (Cont.)Networks and Communication Department
5LogarithmsSlide6
Revision (Cont.)Networks and Communication Department
6General Sine WaveSlide7
Revision (Cont.)Networks and Communication Department
7Slide8
Revision (Cont.)Networks and Communication Department
8Slide9
Revision (Cont.)Networks and Communication Department
9Slide10
Revision (Cont.)Networks and Communication Department
10Slide11
Revision (Cont.)Networks and Communication Department
11Slide12
Chapter 3 (Data & computer communications)Networks and Communication Department
123.1(a)
3.23.3
3.4
3.5
3.6
3.7
3.16
3.17
3.18
3.19
3.21
3 more question on ch3.Slide13
QuestionNetworks and Communication Department
133.1) a)
For the multipoint configuration, only one device at a time can transmit. Why
?Slide14
Answer Networks and Communication Department
14If two devices transmit at the same time, their signals will be on the medium at the same time, interfering with each other; i.e., their signals will overlap
and become garbled.Slide15
QuestionNetworks and Communication Department
153.2)
A signal has a fundamental frequency 1000 Hz what is it's period? Slide16
Answer Networks and Communication Department
16Period = 1/1000 = 0.001 s (×103) = 1
ms.Slide17
QuestionNetworks and Communication Department
173.3)Express
the following in the simplest form you can:a) sin(2π
ft
-π ) + sin(2π
ft
+π)
b) sin 2π
ft
+ sin(2π
ft
-π )Slide18
Answer Networks and Communication Department
18Using:
Sin (A+B)=sin (A) cos (B) + cos (A) sin (B)Sin (A- B) = sin (A) cos (B) - cos (A) sin (B
)
a)
= sin 2
ft . cos
- cos 2
ft . sin
+ sin 2
ft . cos
+ cos 2
ft . sin
=
-2 sin 2
ft
OR
Using
Sin(A+B) + Sin(A-B) = 2 sin (A) cos (B
)
= 2 sin
(2
ft) . cos
= -2 sin 2
ft Slide19
Answer(Cont.)Networks and Communication Department
19 b)
= sin 2
ft + sin 2
ft . cos
+ cos 2
ft . sin
= 0 Slide20
QuestionNetworks and Communication Department
203.4)Sound may be modeled as a sinusoidal function. Compare the relative frequency and wavelength of musical note. Use 330 m/s as the speed of sound and the following frequencies for the musical scale
Note
C
D
E
F
G
A
B
C
Frequency
264
297
330
352
396
440
495
528Slide21
Answer Networks and Communication Department
21
Note
C
D
E
F
G
A
B
C
Frequency
264
297
330
352
390
440
495
528
Frequency deference
33
33
22
44
44
55
33
Wavelength
1.25
1.11
1
0.93
0.83
0.75
0.67
0.63Slide22
QuestionNetworks and Communication Department
223.5)If the solid curve in Figure 3.17 represents sin(2
t), what does the dotted curve represent? That is, the dotted curve can he written in
the form
A sin (2
ft +
); what are A, f and
?Slide23
Answer Networks and Communication Department
232 sin(4πt + π ); A = 2, f = 2, = πSlide24
QuestionNetworks and Communication Department
243.6)
Decompose the signal (1+0.1cos 5t) cos 100t into a linear combination of sinusoidal, function amplitude ,frequency, and phase of each component hint:
use the identity for cos a cos b
.Slide25
Answer Networks and Communication Department
25= cos 100t + 0.1 cos 5t cos 100t.From the trigonometric identity
cos a cos b = (1/2)[ cos(
a+b
) + cos(a–b)
]
,
this equation can be rewritten
as the
linear combination of three
sinusoids
cos
100t + 0.05 cos 105t + 0.05 cos
95t
A=1
F=15.96
=0
A=0.05
F=16.72
=0
A=
0.05
F=15.13
=0Slide26
QuestionNetworks and Communication Department
26 3.7)
Find the period of the function f(t) =(10 cos t )
2
?Slide27
Answer Networks and Communication Department
27cos a cos b = (1/2) [ cos(a+b) + cos(a–b)
]f(t) = 50 cos 2t +
50
The period of cos(2t) is π and therefore the period of f(t) is π .Slide28
QuestionNetworks and Communication Department
283.16)A digital signaling system is required to operate at 9600 bps.
a- if a signal element encodes a 4-bit word, what is the minimum required bandwidth of the channel?
b-
Repeat part (a) for the case of 8-bit words.Slide29
Answer Networks and Communication Department
29Using Nyquist's equation:
C = 2B log2M
We have C = 9600 bps
a.
log
2
M = 4, because a signal element encodes a 4-bit word
Therefore, C = 9600 = 2B × 4, and B = 1200 Hz
b.
9600 = 2B × 8, and B = 600 HzSlide30
QuestionNetworks and Communication Department
303.17)What is the thermal noise level of a channel with a bandwidth of 10 kHz carrying
1000 watts of power operating at 50°C?Slide31
Answer Networks and Communication Department
31N = 1.38 × 10–23 × (50 +
273.15)
=
445.947×
10
–23
watts/HzSlide32
QuestionNetworks and Communication Department
323.18)Given the narrow (usable) audio bandwidth of a telephone transmission facility,
a nominal SNR of 56dB (400,000), and a certain level of distortion,
a.
What is the theoretical maximum channel capacity (kbps) of traditional
telephone
lines?sSlide33
Answer Networks and Communication Department
33Slide34
QuestionNetworks and Communication Department
343.19)Consider a channel with a 1-MHz capacity and an SNR of 63.
a. What is the upper limit to the data rate that the channel can carry?
b.
The result of part (a) is the upper limit. However, as a practical matter,
better error
performance will be achieved at a lower data rate. Assume we choose a
data rate
of 2/3 the maximum theoretical limit. How many signal levels are needed
to achieve
this data rate?Slide35
Answer Networks and Communication Department
35Slide36
QuestionNetworks and Communication Department
363.21)Given a channel with an intended capacity of 20 Mbps, the bandwidth of the
channel is 3 MHz.
Assuming white thermal noise, what signal-to-noise ratio is required
to achieve
this capacity?Slide37
Answer Networks and Communication Department
37Slide38
Question Networks and Communication Department
381- find the bandwidth for the
signal:(4/π)[ sin(2πft
) + (1/3)sin(2π(3f)t) + (1/5)sin(2π(5f)t) +(1/7)sin(2π(7f)t) ]Slide39
Answer Networks and Communication Department
39Bandwidth = 7f-f=6fSlide40
QuestionNetworks and Communication Department
402- a signal with a bandwidth of 2000 Hz is composed of two sine waves. the first one has a frequency of 100 Hz with a maximum amplitude of 20, the second one has a maximum amplitude of 5. draw the frequency spectrumSlide41
AnswerNetworks and Communication Department
41B=2000F=100B=
fh-fL2000=fh-100=2100HzSlide42
QuestionNetworks and Communication Department
423- find the DC component of the following signal.Slide43
AnswerNetworks and Communication Department
43DC component =13Slide44
Any Questions ?The End
44Networks and Communication Department