TMA 1 Telecommunication Principles 2016
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Transcript of TMA 1 Telecommunication Principles 2016
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TEE213/05 Telecommunication Principles Sem1/2016
TEE 213/05
Telecommunication Principles
Tutor-marked Assignment 1
Evidence of plagiarism or collusion will be taken seriously and the University
regulations will be applied fully. You are advised to be familiar with the University’s
definitions of plagiarism and collusion.
Instructions:
1. This is an individual assignment. No duplication of work will be tolerated.
Any plagiarism or collusion may result in disciplinary action in addition to
ZERO mark being awarded to all involved.
2.
You are required to submit your answers through the Online Assignment
Submission (OAS) system and it is your responsibility to submit your TMA
correctly and timely. OAS system doesn’t allow re-submission of assignment.
3. The total marks for TMA 1 is 100% and contributes 25% towards the total
grade. Marks will be awarded for correct working steps and answer.
4. TMA 1 covers topics from Unit 1 and Unit 2.
5.
TMA 1 contains five questions. Answer all parts in English.
6. Your assignment must be word processed in Time New Roman text font size
12 with 1.5 line spacing. Any additional appendices or attachments must be
placed at the end of the submitted document.
7. Include a cover page for your TMA including name, student ID, email
address, course name and code.
8.
You are highly encouraged to passage your TMAs to the Turnitin system
before submission, to encourage honest academic writing and it is not
mandatory except for Project courses.
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TEE213/05 Telecommunication Principles Sem1/2016
Question 1
(a) With the aid of diagrams, explain TWO (2) differences between simplex, half
duplex and full duplex mode of communication.
[9 marks]
(b) A 10kW carrier wave is amplitude modulated at 80% depth of modulation by
a sinusoidal modulating signal.
Determine:
i. the sideband power
[4 Marks]
ii. the total power
[4 Marks]
iii.
the transmission efficiency of the AM wave
[3 Marks]
Question 2
(a) A carrier wave of frequency 10MHz and peak value 10V is amplitude
modulated by a 5kHz of amplitude 6V.
Answer the following questions:
i. Determine the modulation factor.
[2 Marks]
ii. Determine the sideband frequencies.
[2 Marks]
iii. Determine the amplitude of sideband components.
[2 Marks]
iv. Draw the frequency spectrum.
[4 Marks]
(b) A frequency modulated wave is given by the equation:
= 12cos6 × 108 + 5 sin 1250 Find:
i. the carrier frequency.
[2 Marks]
ii. the signal frequency.
[2 Marks]iii. the modulation index.
[2 Marks]
iv. the maximum frequency deviation.
[2 Marks]
v. the power dissipated by the FM wave in 10Ω resistor.
[2 Marks]
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TEE213/05 Telecommunication Principles Sem1/2016
Question 3
(a) A radio station, 1280AM, is conducting a monthly test of the Emergency Alert
System. The test begins with an annoying sound comprised of two pure tones
at 853Hz and 960Hz. The signal being broadcast has exactly five frequency
components.
The signal could be written as follows:
vAM(t) = v1 sin(2π f 1 t) + v2 sin(2π f 2 t) + v3 sin(2π f 3 t) + v4 sin(2π f 4 t) + v5
sin(2π f 5 t) [V]
Find the five frequencies that comprise the AM signal being broadcast. The
carrier frequency and the two sidebands for each of the two tones will be
involved.
[5 marks]
(b) Consider a FM modulator with modulation index m = 5, modulating signal
vm = 2 sin(2π5k t), and an unmodulated carrier frequency f c = 400 kHz, answer
the following questions:
i. Number of sets of significant sidebands
[2 Marks]
ii. Sideband amplitudes
[9 Marks]
iii. Draw the output frequency spectrum
[4 Marks]
[Hint: refer to Bessel Table]
Question 4
(a) Draw Amplitude – Shift Keying (ASK) signal and Frequency – Shift Keying
(FSK) signal for the following data: 101010001101.
[10 Marks]
(b) In general, digital signals are stored after the analog-digital (A/D) conversion
in a digital memory, e.g. the main memory. In order to convert digital signals
back to analog signals, digital-analog (D/A) converters are needed. This
relationship is illustrated in Figure 1:
Figure 1
http://en.wikipedia.org/wiki/Emergency_alert_system#Technical_concepthttp://en.wikipedia.org/wiki/Emergency_alert_system#Technical_concepthttp://en.wikipedia.org/wiki/Emergency_alert_system#Technical_concepthttp://en.wikipedia.org/wiki/Emergency_alert_system#Technical_concept
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i. We consider ′ the recovered, analog signal after the sampling and
quantization. Why is an errorless reconstruction of the analog signal
not possible even assuming ideally working components?
[2 Marks]
ii. Name two advantages of digital signals over analog signals.
[8 Marks]
Question 5
(a) The signal shown in Figure 2 was sampled and quantized. The variance of
quantization error is 2.0833. Compute the following:
Smax=30
Smin=-10
0
Δ
Figure 2
i. Total number of levels.
[Hint: σ2 = △2/12][3 Marks]
ii. The number of bits required to represent each sample.
[3 Marks]
(b) Assume that the word “Freddy” needs to be transmitted through a transmission
line. Using the attached ASCII table in the appendix, answer the following
questions:
i. How many bits are needed by this transmission?
[6 marks]
ii. Using the odd parity for the VRC and even parity for LRC, compute
the VRC and LRC for this transmission.
[8 marks]
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Appendix
Bessel Table
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ASCII Table
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ASCII Table
END OF TMA 1