RAE3601/101/0/2018

Tutorial Letter 101/0/2018

Radio Engineering III (Theory)

RAE3601

Year module

Department of Electrical and Mining Engineering

This tutorial letter contains important information

about your module.

BARCODE

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CONTENTS Page

1 1 INTRODUCTION ....................................................................................................................... 3

2 PURPOSE OF AND OUTCOMES FOR THE MODULE................................................................ 3

2.1 Purpose ........................................................................................................................................ 3

2.2 Outcomes ..................................................................................................................................... 3

3 3 LECTURER(S) AND CONTACT DETAILS ................................................................................ 4

3.1 Lecturer(s) .................................................................................................................................... 4

3.2 Department ................................................................................................................................... 4

3.3 University ...................................................................................................................................... 4

4 4 RESOURCES ............................................................................................................................ 4

4.1 Prescribed books .......................................................................................................................... 4

4.2 Recommended books ................................................................................................................... 4

4.3 Electronic Reserves (e-Reserves) ................................................................................................. 4

4.4 Library services and resources information ................................................................................... 5

5 STUDENT SUPPORT SERVICES ................................................................................................ 5

6 STUDY PLAN ............................................................................................................................... 5

7 PRACTICAL WORK AND WORK-INTEGRATED LEARNING ..................................................... 5

8 ASSESSMENT ............................................................................................................................. 5

8.1 Assessment criteria ....................................................................................................................... 5

8.2 Assessment plan .......................................................................................................................... 5

8.3 General assignment numbers ....................................................................................................... 6

8.3.1 Unique assignment numbers ........................................................................................................ 6

8.3.2 Due dates for assignments ........................................................................................................... 6

8.4 Submission of assignments .......................................................................................................... 7

8.5 The assignments .......................................................................................................................... 8

8.6 Other assessment methods ........................................................................................................ 21

8.7 The examination ......................................................................................................................... 21

9 FREQUENTLY ASKED QUESTIONS ........................................................................................ 21

10 SOURCES CONSULTED ........................................................................................................... 21

11 IN CLOSING ............................................................................................................................... 21

12 ADDENDUM ............................................................................................................................... 21

RAE3601/101/0/2018

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1 1 INTRODUCTION

Dear Student

Welcome to the subject Radio Engineering III (Theory) (RAE3601) at UNISA. This tutorial

letter serves as a guideline to this subject. It provides you with general administrative

information as well as specific information about the subject. Read it carefully and keep it safe

for future reference. We trust that you will enjoy this course.

2 PURPOSE OF AND OUTCOMES FOR THE MODULE

2.1 Purpose

The purpose of this module is to equip students with knowledge that will enable them to apply

analytical and practical techniques and knowledge related to Radio Engineering III.

Communicate in a professional way using the language concepts, models, techniques and

equipment encountered in the engineering working environment. Apply mathematical

techniques and interpret results of mathematical calculations to assist in solving engineering

problems.

2.2 Outcomes

Identify, design and build different types of amplifiers for either transmitting or receiving

radio frequencies.

Understand the working of oscillators from low to ultra high frequencies (UHF).

Know the importance of RF amplifiers and mixers and how these circuits are integrated in

a simple receiver.

Understand the concept of modulation and demodulation in radio circuits.

Design a balanced modulator and have a better understanding of single-sideband

principles.

Have a broader view of FM transmitters and receivers. Be able to design a FM

transmission and receiving circuits on a small scale.

Understand digital transmission and reception.

Understand the transmission of signals and the factors that influence signals as they are

being propagated.

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Know antenna terminology and the construction of different types of antenna arrays.

3 LECTURER(S) AND CONTACT DETAILS

3.1 Lecturer(s)

Your Lecturer for Radio Engineering III is Dr. M. Sumbwanyambe. He can be contacted on

the following e-mail address for any theoretical questions:

E-mail: sumbwm@unisa.ac.za

3.2 Department

Department of Electrical and Mining Engineering: electrical&mining@unisa.ac.za

3.3 University

If you need to contact the University about matters not related to the content of this module,

please consult the publication My studies @ Unisa that you received with your study material.

This brochure contains information on how to contact the University (e.g. to whom you can write

for different queries, important telephone and fax numbers, addresses and details of the times

certain facilities are open). Always have your student number at hand when you contact the

University.

4 RESOURCES

4.1 Prescribed books

Modern Electronic Communication / Jeffrey S. Beasley, Gary M. Miller. 9/e or latest.

4.2 Recommended books

There are no recommended books for this module.

4.3 Electronic Reserves (e-Reserves)

There are no electronic reserves for this module.

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4.4 Library services and resources information

For brief information, go to www.unisa.ac.za/brochures/studies

For detailed information, go to the Unisa website at http://www.unisa.ac.za/ and click on

Library.

For research support and services of personal librarians, go to

http://www.unisa.ac.za/Default.asp?Cmd=ViewContent&ContentID=7102.

The Library has compiled numerous library guides:

finding recommended reading in the print collection and e-reserves –

http://libguides.unisa.ac.za/request/undergrad

requesting material – http://libguides.unisa.ac.za/request/request

postgraduate information services – http://libguides.unisa.ac.za/request/postgrad

finding , obtaining and using library resources and tools to assist in doing research –

http://libguides.unisa.ac.za/Research_Skills

how to contact the library/finding us on social media/frequently asked questions –

http://libguides.unisa.ac.za/ask

5 STUDENT SUPPORT SERVICES

Important information appears in your my Studies @ Unisa brochure.

6 STUDY PLAN

Use your my Studies @ Unisa brochure for general time management and planning skills.

7 PRACTICAL WORK AND WORK-INTEGRATED LEARNING

The practical part of this module will be covered in the module RAEPRA3.

8 ASSESSMENT

8.1 Assessment criteria

Your final mark will be calculated by using a ratio of 20% year mark and 80% examination mark.

8.2 Assessment plan

You will find your assignments for this subject in this Tutorial Letter. Assignment 1, 2 and 3 are

compulsory and all assignments will be used in the calculation of your year mark. Please send

the completed assignments to UNISA before the closing dates stated in this section.

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Assignment 1 must be completed on a mark reading sheet.

The mark for Radio Engineering III (Theory) (RAE3601) is calculated as follows:

The year mark contributes to 20%.

The examination mark contributes to 80%

The year mark is based on all the assignment marks obtained and their contribution towards the

final year mark are as shown in the table below:

ASSIGNMENT

NUMBER

CONTRIBUTION

TOWARDS YEAR MARK

1 (Compulsory) 10%

2 (Compulsory) 45%

3 (Compulsory) 45%

TOTAL = 100 %

8.3 General assignment numbers

Assignments are numbered consecutively per module, starting from 01.

8.3.1 Unique assignment numbers

Assignment 1:

Assignment 2:

Assignment 3:

8.3.2 Due dates for assignments

THE CUT-OFF SUBMISSION DATES FOR THE ASSIGNMENTS ARE :

Assignment 1:

Assignment 2:

Assignment 3:

22 May 2017

18 July 2017

5 September 2017

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8.4 Submission of assignments

ALL ASSIGNMENTS (submitted) HAVE TO BE ATTEMPTED!!!!!!!

THE SUBMISSION OF AN EMPTY ASSIGNMENT COVER IS UNACCEPTABLE.

IT IS VERY IMPORTANT TO CONSIDER THE FOLLOWING POINTS:

NO LATE ASSIGNMENT SUBMISSIONS WILL BE ACCEPTED.

KEEP A CLEAR COPY of the assignment for your own reference.

This is IMPORTANT, as assignments do get lost.

Submissions of assignments must be in accordance with “My studies@Unisa”.

Please note that model answers for the assignments will be dispatched to all students within 1

week of the closing date of the assignment. This implies that you cannot submit your

assignment later than the stipulated submission date.

For detailed information and requirements as far as assignments are concerned, see the

brochure my Studies @ Unisa that you received with your study material.

To submit an assignment via myUnisa:

Go to myUnisa.

Log in with your student number and password.

Select the module.

Click on assignments in the menu on the left-hand side of the screen.

Click on the assignment number you wish to submit.

Follow the instructions.

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8.5 The assignments

THE CUT-OFF SUBMISSION DATES FOR THE ASSIGNMENTS ARE :

Assignment 1: (Compulsory)

Assignment 2: (Compulsory)

Assignment 3: (Compulsory)

22 May 2018

18 July 2018

5 September 2018

ASSIGNMENT 1

TO BE COMPLETED ON MARK READING SHEET

Choose the correct answer and write down the number and the letter corresponding to your choice. For example: 1.20 1. 1. What happens when a signal is under sampled in a communication system?

1) Multiplexing is introduced 2) Aliasing is introduced 3) Noise is introduced. 4) Quantization is introduced

Answer 2: Aliasing is introduced 2. Which of the following statements is correct?

1) Attenuation is proportional to the square of the distance between the transmitter and receiver.

2) The measure of noise is usually expressed in terms of the signal-to-sampling (S/S) ratio

3) Electronic communication conducted as one-way communications, is normally referred to as duplex communication.

4) A transmitter is a collection of electronic components and circuits that accepts the transmitted message from the channel and converts it back to a form understandable by humans.

Answer 1: Attenuation is proportional to the square of the distance between the transmitter and receiver. 3. The picture below shows a communication system. Which of the following is correct?

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1) A is the receiver and B is transmitter. 2) Both A and B are transmitters. 3) Bothe A and B are receivers. 4) A is a transmitter and B is a receiver.

Answer 4: A is a transmitter and B is a receiver. 4. What kind of multiplexing is shown in the figure below?

1) Time division multiplexing 2) Code division multiplexing 3) Phase division multiplexing 4) Frequency division multiplexing

Answer 4: Frequency division multiplexing 5. A two-stage amplifier has an input power of 25 μW and an output power of 1.5 mW. One stage has a gain of 3. What is the gain of the second stage? 1) 60 2) 3 3) 20 4) 1 Answer 3: 20 6. An amplifier has a gain of 45,000, which is too much for the application. With an input

voltage of 20 μV, what attenuation factor is needed to keep the output voltage from exceeding 100 mV? Let A1= amplifier gain = 45,000; A2 = attenuation factor; AT = total gain.

1) 450 2) 0.1111 3) 5 4) 500

Answer 2: 0.1111 7. An SABC amplifier has an input of 3 mV and an output of 5 V. What is the gain in

decibels? 1) 64.4 2) 20.5 3) 3.22

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4) 1.6667 Answer 1: 64.4 8. A power amplifier with a 40-dB gain has an output power of 100 W. What is the input

power? 1) 100 mW 2) 100 W. 3) 10 W 4) 10 mW.

Answer 4: 10 mW 9. What is the ideal percentage of modulation for maximum amplitude of information

transmission? 1) 20 percent 2) 50 percent 3) 100 percent 4) 1percent

Answer 3: 100 percent 10. The maximum peak-to-peak value of an AM wave is 45 V. The peak-to-peak value of

the modulating signal is 20 V. What is the percentage of modulation? 1) 50 percent 2) 100 percent 3) 30 percent 4) 80 percent

Answer 4: 80 percent 11. How much power appears in one sideband of an AM signal of a 5-kW transmitter

modulated by 80 percent? 1) 5Kw 2) 800 W 3) 80 kW 4) 800 kW

Answer 2: 800 W 12. A collector modulated transmitter has a supply voltage of 48 V and an average

collector current of 600 mA. What is the input power to the transmitter? 1) 28.8 W 2) 48 W. 3) 288 W. 4) 14.4 W

Answer 1: 28.8 W 13. Consider question 12 above again, how much modulating signal power is needed to

produce 100 percent modulation? 1) 28.8 W 2) 14.4 W

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3) 100 W 4) 288 W

Answer 2: 14.4 W 14. What are the relative amplitudes of the fourth pair of sidebands for an FM signal with

a deviation ratio of 8?

1) -0.28 2) 0.17 3) -0.1 4) -0.11

Answer 3: -0.1 15. A video signal contains light variations that change at a frequency as high as 3.5

MHz. What is the minimum sampling frequency for A/D conversion? 1) 3.5 MHz. 2) 3.5 Hz. 3) 7 MHz. 4) 7Hz

Answer 3: 7MHz 16. Compute the alias created by sampling a 5-kHz signal at 8 kHz.

1) 5 kHz 2) 8 KHz 3) 13 kHz 4) 3 kHz

Answer 4: 3 kHz 17. An FM transmitter has an 8.6-MHz crystal carrier oscillator and frequency multipliers

of 2, 3, and 4. What is the output frequency? 1) 206.4 MHz 2) 8.6 MHz 3) 620 kHz 4) 34.4 MHz

Answer 1: 206.4 MHz

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18. A tuned circuit has a resonant frequency of 18 MHz and a bandwidth of 120 kHz. What are the upper and lower cut-off frequencies?

1) 18.06 and 102 MHz. 2) 17.94 and 102 MHz. 3) 102 MHz and 138 MHz. 4) 18.06 and 17.94 MHz.

Answer 4: 18.06 and 17.94 MHz. 19. What is the name of the circuit used at the receiver to recover multiplexed signals?

1) Sampler 2) Multiplexer 3) Amplifier 4) Demultiplexer

Answer 4: Demultiplexer 20. The concept of multiplexing as shown in the figure below is known as:

1) Frequency division multiplexing 2) Time division multiplexing 3) Code division multiplexing 4) Pulse division multiplexing

Answer 2: Time division multiplexing TOTAL= [20]

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ASSIGNMENT 2.

ASSIGNMENT 2 INVOLVES A MINI PROJECT IN WHICH YOU ARE REQUIRED TO TACKLE ONE OF THE FOLLOWING TOPICS. A DESKTOP RESEARCH IS REQUIRED. EACH QUESTION CARRIES 100 MARKS

2.1. Design an FM transmitter for rural area in Mpumalanga. Your report must be not less than 20 pages and must include chapters. Your topic must be: “Designing an FM transmitter for the rural Mpumalanga”.

2.2. Write a report on Radio Over Internet Protocol (ROIP). Your report must be not less than 20 pages and must include chapters. Your topic must be: “Digital transformations: understanding radio over internet protocol in modern day broadcasting”.

2.3. Write a report on different types of antennas. Your report must be not less than 20 pages and must include chapters. Your topic must be: “Analysis of Antennas in wireless communication world”

2.4. Write a report on digital migration in South Africa. Your report must be not less than 20 pages and must include chapters. Your topic must be: “A close look at digital migration in South Africa”.

Note: Your report must have four chapters and well written. More information on how to write the report is available in additional resources on myUNISA. Please Visit myUNISA.

ASSIGNMENT 3

QUESTION 1: Amplitude modulation 1.1. Why is it important that the modulation index should be a number between 0 and 1? (2) Answer 1.1: if the number is above 1 the distortion of the modulated waveform will occur and the intelligence will be lost. 1.2. Sketch the waveform that will arise if the modulation index is above 1 Answer: 1.2:

1.3 What is the modulation index called when it is expressed as a percentage? (2) Answer 1.3: Multiplying the modulation index by 100 gives the percentage of modulation.

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1.4. What is the name of the frequencies that are generated whenever the carrier is modulated by the intelligence? (3) Answer 1.4: Whenever a carrier is modulated by an information signal, new signals at different frequencies are generated as part of the process. These new frequencies, which are called side frequencies, or sidebands, occur in the frequency spectrum directly above and directly below the carrier frequency. 1.5. What is the equation that describes the Amplitude modulation total power that driven through an antenna? (2) Answer 1.5: The total transmitted power PT is simply the sum of the carrier power Pc and the power in the two sidebands PUSB and PLSB. 1.6. Consider a 250W SENTECH signal that is 70% modulated. 1.6.1 What is the total power in each of the sidebands? (2) Answer: 30.63 W 1.6.2. What will be the total power in each sideband if the signal is 100% modulated? (2) Answer: 62.5W 1.6.3 What can you deduce on the results in 1.6.1 and 1.6.2? (2) Answer: More power is generated when the modulation index is close to 1 or 100% 1.6.4. Discuss how you would generate a SSB in an AM modulation and why is it beneficial. (7) Answer: The generation of SSB signal is to suppress the carrier, leaving the upper and lower sidebands. This type of signal is referred to as a double-sideband suppressed carrier (DSSC or DSB) signal. Double-sideband suppressed carrier signals are generated by a circuit called a balanced modulator. The purpose of the balanced modulator is to produce the sum and difference frequencies but to cancel or balance out the carrier. Benefits of SSB: (i) The primary benefit of an SSB signal is that the spectrum space it occupies is only one-half that of AM and DSB signals (ii) All the power previously devoted to the carrier and the other sideband can be channelled into the single sideband, producing a stronger signal that should carry farther and be more reliably received at greater distances. (iii) Because SSB signals occupy a narrower bandwidth, the amount of noise in the signal is reduced. (iv) There is less selective fading of an SSB signal over long distances. [24] QUESTION 2: FREQUENCY RECEIVERS. 2.1. As an SABC technologist you are required by the head of engineering

department to set the SABC FM transmitter to a modulation index of 2.2 and a deviation of 7.48 kHz. What is the maximum modulating frequency needed to achieve the above values? (3)

Answer: 2.1.

2.2. After working as technologist you are require to set up a transmitter in the rural

parts of Mpumalanga. What is the maximum bandwidth of an FM signal if the deviation required for the FM signal is 30 kHz with a maximum modulating signal of 5 kHz? You must determine this using:

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2.2.1. The Bessel table 2.2.2. The Carson’s rule? (2) Answer 2.2.

2.3. Draw a diagram of a phase locked loop (PLL) and explain its operation? (8)

Answer 2.3: A phase-locked loop or phase lock loop (PLL) is a control system that generates an output signal whose phase is related to the phase of an input signal. There are several different types; the simplest is an electronic circuit consisting of a variable frequency oscillator and a phase detector in a feedback loop. The oscillator generates a periodic signal, and the phase detector compares the phase of that signal with the phase of the input periodic signal, adjusting the oscillator to keep the phases matched. Keeping the input and output phase in lock step also implies keeping the input and output frequencies the same. Consequently, in addition to synchronizing signals, a phase-locked loop can track an input frequency, or it can generate a frequency that is a multiple of the input frequency.

2.4. A superheterodyne receiver must cover the range from 220 to 224 MHz. The first IF

is 10.7 MHz; the second is 1.5 MHz. Find: 2.4.1. The local oscillator tuning range. (2) 2.4.2. The frequency of the second local oscillator. (2) 2.4.3. The first IF image frequency range. (2) (Assume a local oscillator frequency higher than the input by the IF.)

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Answer 2.4

2.5. Suppose you are driving along the Jan smuts avenue listening to 5FM radio.

Suddenly you hear another radio station overriding the 5FM radio. Explain the phenomenon that just happened? (3)

Answer 2.5: What is being experienced is the capture effect in which one signal, usually

the weal one, is completely suppressed by a stronger signal. In this scenario the other FM signal is stronger than the 5FM signal; as such the receiver keeps switching from one signal to another.

2.6. A PLL is setup so that its VCO free runs at 10MHz. The VCO does not change

frequency until the input is within 50kHz of 10Mhz. after that condition, the VCO follows the input to ±200kHz of 10Mhz before the VCO starts to free run again. Determine the lock and the capture ranges of the PLL. (4)

[28] QUESTION 3: DIGITAL COMMUNICATIONS 3.1. Suppose the minimum sampling rate for a low pass signal is 8 kHz, and a guard band of

2 kHz is required. Determine the signal bandwidth. (2) Answer 3.1.

3.2 State Nyquist sampling theorem. (2) Answer 3.2: A bandlimited continuous-time signal can be sampled and perfectly reconstructed

from its samples if the waveform is sampled over twice as fast as its highest frequency component.

3.3 An audio signal is band-limited to 15 kHz. What is the minimum sample frequency if this

signal is to be digitized? (2) Answer 3.3: 2x15=30KHz

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3.4 Discuss how PCM is done for the following cases:

3.4.1. Digital transmission of voice signals in public-switched telephone networks. (3) 3.4.2. Stereo CD-quality music. (3) Answer 3.4.1 A voice signal is essentially limited to a band from about 100 Hz to 3100 Hz and frequencies outside this band do not impact voice intelligibility. In PCM, the voice signal is often lowpass filtered at 3.1 kHz and then sampled at a rate of 8000 samples per second. This rate is higher than the Nyquist sampling rate of 6200 samples per second, so realizable filters with reasonable guard bands can be applied for signal reconstruction. Answer 3.4.2. The human ear is sensitive to frequencies up to around 20 kHz. Although the Nyquist sampling rate for music should be 40,000, the actual sampling rate, after using oversampling and then decimation, at the input of the quantizer is 44,100 samples per second. High-quality audio requires finer granularity in quantization, and each sample is thus applied to a 16-bit (65,536-level) quantizer.

3.5 Determine the capacity of a wired dial-up voice-grade telephone line, in which the noise

is assumed to be additive white Gaussian with a signal-to-noise ratio of 35 dB and a usable bandwidth of 3.2 kHz. (3)

Answer 3.6. C= (3200) log2(1+3162)=37.2kbps

[15] QUESTION 4: NOISE 4.1. Define the following terms: 4.1.1. Sensitivity (1) Answer A communication receiver’s sensitivity or ability to pick up weak signals 4.1.2. Bit error rate (BER) (1) Answer BER is the number of errors made in the transmission of many serial data bits. 4.1.3. What is noise? (1) Answer: Noise is an electronic signal that is a mixture of many random frequencies at many amplitudes that gets added to a radio or information signal as it is transmitted from one place to another or as it is processed. 4.2. What is the average noise power of a device operating at a temperature of 90°F with a bandwidth of 30 kHz? (4)

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Answer

4.3. What is the open-circuit noise voltage across a 100-kV resistor over the frequency range of direct current to 20 kHz at room temperature (25°C)? (3) Answer:

4.4. The bandwidth of a receiver with a 75-V input resistance is 6 MHz. The temperature is 29°C. What is the input thermal noise voltage? (3)

[13] QUESTION 5: ANTENNAS

5.1 Define the terminology listed below as used in antennas. 5.1.1 Isotropic antenna (1) 5.1.2 Effective Isotropic Radiated Power (1) 5.1.3 Polarization (1)

Answer 5.1.1 Isotropic antenna - this antenna would be a point source of zero size. It would

Answer 5.1.2: Effective isotropic radiated power – the product of the power supplied to a

transmitting antenna and the gain of the antenna with respect to an isotropic antenna. Answer 5.1.3: Polarization – the orientation of the electric field with respect to earth 5.2 An antenna has a gain of 14 dB. It is fed by an RG-8/U transmission line 25 m long

whose attenuation is 3 dB/10 m at 220 MHz. The transmitter output is 50 W. Calculate: 5.2.1 The transmission line loss (5) 5.2.2 The effective radiated power (3)

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Answer 5.2.1 Total line attenuation: 3.6 dB/10 m

25

= 2.510

2.5×3.6 = -9dB (minus dB indicates a loss)

-1dB =10logP P = log -0.9 = 0.126

POUTP = = 0.126PIN

P = 0.126×50 = 6.3WOUT

Answer 5.2.2 Gain = 14 dB

dB-1 -1Ratio = log = log 1.4 = 25.110

EIRP = 6.3×25.1=158.2W

5.3 Refer to Figure 3. 5.3.1 What is the beam width of this antenna? (1)

5.3.2 Calculate the gain of the antenna (2) 5.3.3 The front-to-back ratio of the antenna in decibels. (2) Answer 5.3.1 Beam width is approximately 11°

Answer 5.3.2 203 203

G = 2log = 2log = 2.532ant beamwidth 11°

Answer 5.3.3 PfF /B =10log dB

Pb

, Pf = forward power and Pb = backward power

Pf = 0 dB 0/10P =10 =1W

b

Pb = -24dB

-24/10P =10 =0.00398Wb

1

F /B =10log = 24dB0.00398

Note: This radiation pattern uses a logarithmic scale and is calibrated in decibels. The maximum radiation point on the major lobe at 0° is given the value of 0 dB. The -3 dB down points a clearly identified so that beam width can be determined.

20

Figure 3

5.4 A very low-power battery-operated transmitter at an inaccessible location is to send telemetry data to a data collection centre. The signal is often too weak for reliable data recovery. List some practical steps that can be taken to improve transmission. (4) Answer 5.4 Using some form of diversity reception techniques (to severe fading problems) such as space diversity, frequency diversity, angle diversity and polarization diversityUsing repeater transmitters

[22]

TOTAL = [100]

Annexure 1: Bessel table

mf J0

(Carrier) J1 J2 J3 J4 J5 J6 J7 J8 J9 J10

0.00 1.00 - - - - - - - - - -

0.25 0.98 0.12 - - - - - - - - -

0.5 0.94 0.24 0.03 - - - - - - - -

1.0 0.77 0.44 0.11 0.02 - - - - - - -

1.5 0.51 0.56 0.23 0.06 0.01 - - - - - -

2.0 0.22 0.58 0.35 0.13 0.03 - - - - - -

2.5 -0.05 0.50 0.45 0.22 0.07 0.02 - - - - -

3.0 -0.26 0.34 0.49 0.31 0.13 0.04 0.01 - - - -

4.0 -0.40 -0.07 0.36 0.43 0.28 0.13 0.05 0.02 - - -

5.0 -0.18 -0.33 0.05 0.36 0.39 0.26 0.13 0.05 0.02 - -

6.0 0.15 -0.28 -0.24 0.11 0.36 0.36 0.25 0.13 0.06 0.02 -

7.0 0.30 0.00 -0.30 -0.17 0.16 0.35 0.34 0.23 0.13 0.06 0.02

8.0 0.17 0.23 -0.11 -0.29 -0.10 0.19 0.34 0.32 0.22 0.13 0.06

9.0 -0.09 0.24 0.14 -0.18 -0.27 -0.06 0.20 0.33 0.30 0.21 0.12

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10.0 -0.25 0.04 0.25 0.06 -0.22 -0.23 -0.01 0.22 0.31 0.29 0.20

8.6 Other assessment methods

None

8.7 The examination

Use your my Studies @ Unisa brochure for general examination guidelines and examination preparation guidelines.

9 FREQUENTLY ASKED QUESTIONS

The my Studies @ Unisa brochure contains an A-Z guide of the most relevant study information.

10 SOURCES CONSULTED

None

11 IN CLOSING

Please ensure that you have all the tutorial letters and prescribed book available before starting with your studies.

12 ADDENDUM

Syllabus

1 Introduction to communication systems

2 Noise

3 Receivers

4 Amplitude Modulation

5 SSB Transmitters and Receivers

6 Digital Communications

7 Transmission Lines

8 Radio Wave Propagation

9 Antennas

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Prescribed book: Modern Electronic Communication, 9/e, Beasley J.S and Miller, G.M

SCHEDULE Activity

To successfully prepare for and submit your assignments you have to work according to a time

table. Use the following table or draw up your own table to schedule your studies for this

subject. This table starts after close of registration; if you register early, adjust the dates.

KNOWLEDGE & COMPETENCE

STUDY UNIT SECTION CONTENT Week Date

TUTORIALS 1 & 2

1 Introduction to communication systems

1 Introduction to dBs

1 4 – 10 March

2 Communication systems terminology

2 Noise

1 Describe a basic communication system and explain the concept of modulation.

2 11 - 17 April

2 Define electrical noise and explain its effect at the first stages of a receiver.

3 Calculate the thermal noise generated by a resistor.

4 Calculate the signal-to-noise ratio and noise figure for an amplifier.

TUTORIALS 3 & 4

3 Receivers

1 Define the sensitivity and selectivity of a radio receiver.

3 18 – 24 May

2 Describe the operation of a diode detector in an AM receiver.

3 Sketch block diagrams of superheterodyne receivers.

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4 Understand the generation of image frequencies and describe how to suppress them.

5 Recognize and analyze RF and IF amplifiers.

6 Analyze the operation of a complete AM and FM receiver system.

7 Describe the operation of an FM receiving system and highlight the difference compared to AM.

8 Sketch a slope detector schematic and explain how it can provide the required response to the modulating signal amplitude and frequency.

9 Explain the operation of the PLL and describe how it can be utilized as an FM discriminator.

4 Amplitude Modulation

1 Describe the process of modulation.

4 25 – 2 May

2 Sketch an AM waveform with various modulation indexes.

3 Explain the difference between a sideband and side frequency.

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4 Analyze various power, voltage, and current calculations in AM systems.

5 Understand circuits used to generate AM.

TUTORIALS 5 & 6

5 SSB Transmitters and Receivers

1 Describe how an AM generator could be modified to provide SSB.

5 3 – 9 June

2 Describe various types of SSB and explain their advantages compared to AM.

3 Explain circuits that are used to generate SSB in the filter method and describe the filter s that can be used.

4 Analyze the phase-shift method of SSB.

5 Describe several methods used to demodulate SSB systems.

6 Determine the frequencies at all points in an SSB receiver when receiving a single audio tone

TUTORIAL 7 7 Digital Communications

1 Describe the quantization process in a PCM system in terms of how it is created, how to determine the Nyquist sampling frequency, and how to define quantization levels.

6 10 – 16 June

RAE3601/101/0/2018

25

2 Determine the dynamic range and signal-to-noise ratio of a PCM system.

8 Transmission Lines

1 Describe the operational characteristics of twisted-pair cable and its testing considerations.

7 17 – 23 July

2 Describe the physical characteristics of standard transmission lines and calculate Zo.

3 Calculate the velocity of propagation and the delay factor.

4 Analyze wave propagation and reflection for various line configurations.

5 Describe how standing waves are produced and calculate the standing wave ratio.

Assignment 2

should be ready

for

submission

TUTORIAL 8

9

Radio Wave Propagation

1 Discuss the makeup of an electromagnetic wave and the characteristic of an isotropic point source.

8 24 – 30 July

2 Explain the processes of wave reflection, refraction, and diffraction.

26

3 Describe ground, and space wave propagation and calculate the ghosting effect in TV reception.

4 Calculate the approximate radio horizon based on antenna height.

5 Discuss the effects of the ionosphere on sky-wave propagation.

TUTORIAL 9

10 Antennas

1 Describe the development of a half-wave dipole antenna from transmission line theory.

9 31 – 6 August

2 Define the properties of antenna reciprocity and polarization.

3 Calculate and define antenna efficiency

4 Calculate power received and transmitted using Friis equation. Design different types of antenna configurations.

11 Revision

10 7 – 13 September