Analogue Circuits

Home Admissions Course Guide Analogue Circuits

This Course Guide has been taken from the most recent presentation of the course. It would be useful for reference purposes but please note that there may be updates for the following presentation.


Analogue Circuits

Welcome to ELEC S225, Analogue Circuits.

This course was adapted from the course T202 Analogue and Digital Electronics by the Open University in the U.K. Some aspects of the course presentation, however, are very different here in Hong Kong from the way they are in Britain. The main differences relate to the practical work associated with the course. In Britain, students are sent a 'Home Kit' consisting of electronic components, circuit modules, and a 'Generatorscope' (a combined oscilloscope, signal generator, and power supplies). With this kit, they are expected to carry out a large number of experiments in their own homes. We do not issue a home kit at HKMU, but instead, you are expected to attend several 'short laboratory' sessions where you will carry out the same experiments. Don't be confused by references in the course texts to 'home kits', 'home experiments', or 'the Generatorscope' — they are not relevant to you. You may also find references to 'Summer School'. This is a whole week of practical work, tutorials, and lectures that OUUK students must attend. Here in Hong Kong, the same experiments are carried out at 'long laboratory' sessions held on Sundays later in the course.

The course ELEC S222 Electronics Principles and Digital Design is recommended as a co-requisite of ELEC S225. You are assumed to have studied Unit 1 of ELEC S222 or had knowledge in basic electronic circuits. Please refer to ELEC S222 Unit 1 (i.e. T202 Block 1) for background information on basic electronic principles.

This Course Guide has been designed to provide you with some essential information about the course and to assist you in planning the best use of your available study time. Sections 2 to 6 present an overview of the course, and therefore help you see the course as a whole. You should, therefore, read these sections before you start work on Unit 1.

The Presentation Schedule is available on the Online Learning Environment (OLE), which shows how long you should spend studying each unit of the course. This schedule can help you to do the overall planning of your 34 weeks of study. To assist your detailed planning, Section 6 of this Guide contains detailed study guides to each of the units in the course, showing how you are expected to allocate your time to each of the individual components of a unit. You will need to read the relevant Unit Guide each time you start your study of a new unit. These unit guides will assist you in planning the detailed allocation of your study time week-by-week as you progress through the course. Section 6 also contains some 'study notes' that explain ideas or terms used in the texts with which U.K. students are assumed to find familiar, but which you may find confusing.

If during your study of the course, you have difficulty understanding the course materials, you should contact your tutor, whose name, address, and telephone number will be supplied to you by the HKMU Registry.

If you have not received course materials that you believe have been dispatched to you, or if the materials you receive are incomplete, you should contact the Course Materials Distribution Office (ALTO) at 2768 6446.

If you have any problems other than subject matters in the course materials or have any suggestions for improvements, please write to:

The ELEC S225 Course Coordinator,
School of Science and Technology,
Hong Kong Metropolitan University
30 Good Shepherd Street
Homantin, Kowloon

It is important in electronics to be able to do more than 'get the right answer' to a specific set of questions. As in all fields of study in which design is a major activity, the main task is to be able to solve new problems as well as to know the answers to previously solved problems. Upon completion of this course, you should be able to:

  1. design a circuit to meet a new performance specification,
  2. explain the reason why you have designed a circuit the way you have,
  3. diagnose the cause of an unfamiliar fault or a new sort of circuit behaviour so that you can correct it,
  4. argue the good and bad points of different circuits and ask important questions about them, and so on.

The common feature of all these activities is having the ability to cope sensibly with new and unexpected problems. So it is this 'capability', as it is called, that this course tries to help you acquire.

There are subsidiary aims that are much easier to teach and to learn which undoubtedly form part of the capability that the course is trying to help you develop. There are some tried and tested circuits that you ought to know about and whose performance you should be able to describe precisely. They often form the starting point for any one of the problem-solving tasks listed above. Equally, there are several techniques available, like using mathematics or drawing circuit diagrams, which help you analyse a problem in preparation for devising a solution to it. Knowing about these circuits and being able to use these techniques are the beginnings of electronic capability, and they are usually referred to as knowledge and skills. But understanding the circuits and how they are used, and grasping the concepts on which they depend are the key parts of capability. Capability is being able to use such knowledge and skills to solve new problems. It is the ability to go beyond the information given.

The course sets self-assessed questions (SAQs) and assignments to test your knowledge and skills, but to gain the understanding that you need requires you to tackle new problems, or at least problems that are new to you; to try to design things, to try to explain things in your own words, to try to diagnose faults, to ask sensible questions and so on. There may be no 'right' answers to these questions, they are developed to reveal to yourself, as well as to your tutor, your degree of understanding. Giving you model answers merely tempts you to learn the answers by heart instead of thinking about the problem. So the 'answers' that are provided may refer only to the sort of things you should have thought about. In trying to answer such assignments, the important thing is not whether you can solve the problem quickly, but whether you can show that you have understood the problem and can see how to tackle it successfully. Unfortunately, ELEC S225 does not have time to set testing projects that fully test your problem-solving skills (The project course such as ELEC S402 does that), but it may pose some open-ended problems that you would be expected to analyse, so that it can be seen if you are taking a sensible approach.

To make it clear that you are being asked to learn both knowledge and skills, as well as to acquire understanding, the course includes two kinds of objectives. The specific objectives are those you are used to. They lead to questions about what you know and about the calculations that you should be able to do. The general objectives lead to questions whose aim is to bring out what you understand and to reveal whether you have grasped the important concepts on which understanding depends.

The course contains many different components, closely integrated to produce a coherent teaching package. These components are as follows.


3.1 The main texts. These texts form the main teaching medium of the course, and you will spend most of your time reading these texts and answering the self-assessment questions (SAQs) that they contain. You must tackle the SAQs as you read through a unit text, as they are the main means you have of testing whether you have understood the contents. These texts are arranged in units, with most units having several parts. The units vary in length, and the individual parts within a unit are also usually of different lengths.


3.2 The glossary. The course glossary lists each of the new terms and concepts introduced in the course, with a very brief description of each and an indication of where, in the main texts, the term is introduced and described. Whenever a term is used, and you can't remember the meaning of it, you should first look in the glossary. The short description there may serve to refresh your memory. If that description doesn't help, you should refer back to the main text where the term has been described in detail.


3.3 Home computing. Throughout the course, some home computing exercises require you to use Computer-Aided Design (CAD) software known as OrCAD to analyse circuit behaviour. These computing exercises are an essential component of the course, and the CAD software is provided as part of the course materials. You are required to have access to an IBM PC or compatible running Windows 7 or above and English Windows is preferred. You will find the software NODALOU and LOGANOU used in the main text. You can simply ignore them because OrCAD has replaced these old software packages.

You are assumed to have prior knowledge in installing and operating OrCAD (e.g. you have studied Block 1 of ELEC S222). If you did not use OrCAD before, you don't need to worry. Please visit ELEC S225 OLE page and download Home Computing Book 1 for reference.


3.4 Short laboratories. Several 'short laboratory' sessions spread throughout the course will be held in HKMU's laboratory on the Homantin campus. At these sessions, you will carry out experiments designed to reinforce the teaching of skills and knowledge and to assist in developing understanding. While attendance at these sessions is optional, much of the teaching in the texts assumes you have performed the experiments, so if you do not attend the texts will be harder to understand and learn from. Also, some of the assignments may contain questions that you might not be able to answer fully unless you have attended the short laboratory sessions. The detailed information of the short labs. will be provided in Stop Presses.


3.5 Long laboratories. There are two 'long laboratory' sessions to be held on Sundays in the HKMU laboratory near the end of the course. Each of these long labs lasts for a whole day and provides an opportunity for you to engage in realistic design exercises, as well as to perform extended experiments to reinforce the teaching of essential concepts. Attendance at these sessions is compulsory. If you do not attend, you cannot pass the course.  The detailed information of the long labs. will be provided in Stop Presses.


3.6 Tutorials. There will be regular tutorial sessions with your tutor, supporting the teaching in the main texts. Exact information about the date, time, and place of each tutorial will be provided in Stop Presses. Attendance at tutorials is optional.


3.7 Surgeries. Regular surgery sessions are scheduled throughout the course, a tutor will be available to answer specific problems that you may have with the course work. These 'surgery' sessions are intended to provide you with specific assistance with specific problems; the tutor will not run a tutorial, and will not have facilities for talking to more than a few students at a time. The surgeries provide the opportunity for you to resolve difficulties without having to wait for your next scheduled tutorial. Details of these surgery sessions will be sent to you in Stop Presses.


3.8 OLE. This course will use the Online Learning Environment (OLE). You are recommended to visit the OLE regularly. The webpage address is:

The ELEC S225 Study Units will use the following blocks from T202.


S225 Study UnitT202 Study Block
Unit 1Block 2
Unit 2Block 4 parts 1 and 2
+ Supplementary Readings
Unit 3Block 5
Unit 4Block 7
Unit 5Block 8
Unit 6Block 9

Since ELEC S225 only uses part of the T202 course material, you can ignore the references to the unused blocks in T202.


Unit 1  Analogue Principles (T202 block 2)

Part 1: Phasor Analysis
This first part of Unit 1 develops the basic ideas necessary for the analysis of a.c. circuits, namely, phasors, phasor diagrams, phasor notation, the operator j, complex numbers, phasor manipulations using complex numbers, and phasor operators. It then uses these tools to analyse some simple a.c. circuits and to obtain the voltage transfer function of these circuits. It contains short lab experiments and some home computing exercises.

Part 2: Frequency Response of Linear Circuits
This text is concerned with how the voltage transfer function of a circuit changes with frequency, and in particular with the Bode plot as a graphical means of representing and interpreting those changes. It develops the Bode plots for several simple a.c. circuits, and examines the frequency response of both the series and parallel resonant RLC circuits. Again, there are both short labs and home computing exercises associated with this part of the unit.

Part 3: Amplifiers and Feedback
This text applies the ideas of a.c. circuit analysis developed in earlier parts of the unit to the analysis of the performance of the operational amplifier circuits. It deals with the frequency response of an operational amplifier, then examines the frequency response of a range of feedback amplifier configurations. The idea of instability is introduced, and the conditions affecting the stability of a feedback amplifier are discussed. It ends with a discussion of active filters, and the Wien bridge oscillator as an example of the use of positive feedback. Both short labs and home computing exercises are included.


Unit 2 Transistors and basic circuits (T202 block 4, parts 1 & 2)

Part 1: p-n junctions and transistors (Part 1 of T202 block 4)
This first part of the unit looks at some of the physics underlying semiconductor devices and explains the properties of diodes and transistors in terms of the properties of silicon and the structure of the devices. It also explains one application of the d.c. characteristics of the devices, and the design of d.c. current sources using transistors.

Part 2: Analogue Transistor Circuits (Part 2 of T202 block 4)
This part of the unit is concerned with constructing useful analogue transistor circuits using the knowledge of devices gained in Part 1. The text first looks at the way a transistor can be represented by an equivalent circuit, and how numerical values for the equivalent circuit parameters are obtained from datasheets and graphs of transistor characteristics. It then describes the common-emitter amplifier, the use of a dynamic load, the long-tailed pair, and the emitter follower. These four circuit configurations are finally combined into the design of a simple operational amplifier. The home computing exercises associated with this part of the unit allow you to investigate the d.c. and small-signal behaviour of the circuits described in the text.

Supplementary Readings on MOSFET.


Unit 3 Audio Amplifier Design (T202 block 5)

Although this unit is specified as being split into 5 separate parts, each part is smaller than for previous units and the divisions between parts are not as clear.

The first part of the unit describes some characteristics of signals and noise, in particular: average value, mean-square value, the Gaussian distribution, line spectrum, and power density spectrum. The second part discusses some of the components of a hi-fi audio system and their characteristics, including the magnetic pick-up for a record turntable, the loudspeaker, and the amplifier. Amplifier characteristics considered are: output offset voltage, noise sources, frequency response, transient response, and distortion. The last three parts of the unit are all concerned with the design of an audio amplifier to satisfy a given specification. The required specification is first developed, a pre-amplifier designed using a 741 operational amplifier, and finally, the power output stage is designed using both an op-amp and discrete components. The unit contains both short labs and home computing exercises. The experiments involve building and testing the audio amplifier, while the home computing exercises are used to simulate the performance of the designed amplifier and hence predict its performance.


Unit 4 Power Supplies (T202 block 7)

This unit describes how to obtain a stable, d.c., low voltage source from an a.c. mains supply. It deals with: half- and full-wave rectification, the bridge rectifier, voltage references, regulation, overload protection, and switched-mode power supplies. Home computing exercises require you to simulate various sub-systems of the overall regulated power supply to examine their performance characteristics.


Unit 5 Higher-Frequency Circuits (T202 block 8)

Part 1: The Hybrid-p Equivalent Circuit
This first part of the unit explains the performance of transistors and transistor circuits at higher frequencies, that is, frequencies at which the effects of small capacitances within the transistor and/or within the circuit become significant. The transistor is represented by the hybrid-p equivalent circuit which effectively represents the transistor performance at all practical frequencies. Using that equivalent circuit, the behaviour of a common-emitter amplifier is analysed. You are required to check the calculated amplifier behaviour by simulating it on your home computer.

Part 2: Interconnections
This part of the unit is about the various methods of connecting signals from one place to another. It considers the following interconnection methods, and some of the do's and don'ts associated with each: open wires, twisted pairs, twin feeders, coaxial cables, multi-way cables, strip-lines, optical fibres, and transmission lines.

The text also discusses the connection of test gear to high-frequency circuits, digital circuit characteristics at high frequencies, and the characteristics of printed circuit board connections.


Unit 6 Radio Frequency Techniques (T202 block 9)

Part 1: Modulation, Demodulation, Propagation and Aerial Systems
This part describes the basic principles of transmitting and receiving information by radio waves. It deals with the modulation, propagation, and demodulation of signals, and describes the types of aerial systems used to receive the transmitted signals.

Part 2: Radio Receivers
The second part of this unit is devoted entirely to radio receivers. It explains basic principles and shows how these principles are applied to the radio receivers in your home. Another short lab provides the opportunity to build and test a small radio receiver.

The assessment of this course consists of a continuous assessment component and a final examination. Your progress throughout the course (the continuous assessment component) will be assessed through four assignments. All the assignments are required for assessment purposes, which means that the marks you obtain for these assignments will be used in calculating your overall course mark. At the end of the course, you will be required to sit a three-hour examination.

Your overall course mark will be calculated from the results of your assignments and your examination result as follows:

Four Assignments (all equally weighted) 50%
Final Examination 50%
TOTAL 100%

Assignments 01, 02, and 04 are used to assess your progress with the main texts, the home computing, and the short labs. Assignment 03 will assess your performance in the long laboratories.

The final examination is a written paper of three hours, and you will attempt the questions without the help of any notes or printed materials relating to the course. A simple scientific calculator is allowed. You will be given a Specimen Examination Paper, which resembles the actual paper in both style and format so that you can get some idea of what to expect.

The course grade is mainly determined by the overall course score (CS) yet students are normally required to obtain a minimum in both overall examination score (OES) and overall continuous assessment score (OCAS) set by the University to obtain a Pass result. To be awarded a particular course grade, the student must meet the minimum CS set by the Award Committee.



This course is designed to help you move easily from the required readings to the assignments and the examination. You are expected to apply the information and techniques presented during the course when completing the assignments.

You must submit assignments to your tutor for formal assessment following the due dates stated on each assignment. The due dates can also be found on the Presentation Schedule. The self-tests or SAQs are, by definition, not part of your formal assessment, but you must complete them as you work through the units. They not only expose you to the types of problems you are required to complete for the assignments, but they also reflect the demands of the unit objectives and are designed to help you understand and apply the principles covered in the units.


E-submission of Assignments

There are four assignments for this course. These are all assignment exercises. You are required to submit your assignments via the e-submission in the OLE. You must submit the assignments on or before the corresponding due date. You can prepare your assignments using word processing software (e.g. Word) and then upload the pdf file to the OLE. Or you can complete your assignments on paper and convert them to soft copy by scanning or taking pictures. The recommended format is pdf (the file size should be less than 10 MB).

Your tutor will mark these assignments. Each assignment has a weighting of 12.5%. The assessment component is worth 50% of the total course mark.


How to do your assignments

For each assignment, first, read quickly through the description of the problem in the Assignment File. Make brief notes on what you believe are the key points raised. Next, carefully read the description two or three times while referring to your notes. Make sure that you have identified all the key points. Then, read the instructions that accompany the problem. These explain what you are required to do. Make sure you understand what is required and that your assignment provides what is required.

When you have completed the assignment, you should submit your assignment via the e-submission in the OLE. Make sure that each assignment is uploaded to the OLE before the due date. Marks may be deducted for work that is late without prior authorization. If, for any reason, you cannot complete your work on time, contact your tutor before the assignment is due. This is to discuss the possibility of an extension. Extensions will not be granted after the due date unless there are extremely exceptional circumstances.

You should use references other than your textbooks or work when researching the answers for your assignments. Make sure that you reference your work properly. If you do not, you commit plagiarism and will be penalized severely. Plagiarism is the theft of somebody else's work or ideas. This applies just as much to using the work of other students as it does to the authors of books. If you use somebody else's ideas in your work, give them credit for it. You do this by referencing. In the body of the work, this appears as (Stallings, 2016) for example. At the end of your assignment, list all of your references alphabetically in a section called 'References'. Include the full name, title, date, and place of publication. For instance, one way to cite a reference is:

Stallings, W (2016) Computer Organization and Architecture: Designing for Performance (10th Edition), Hoboken, NJ: Pearson Education.

6.1 The course as a whole

The following table shows the amount of study time allocated to each of the units of the course.


Unit TitleNominal study weeks
1Analogue Principles11
2Transistors and Basic Circuits7
3Audio Amplifier Design7
4Power Supplies2
5Higher Frequency Circuits3
6Radio Frequency Techniques3


How these overall times break down into study times for the individual parts of each unit is described in each of the detailed unit study guides that follow. Before starting to study each unit, you should read the detailed study guide for that unit to plan the use of your time effectively. The Presentation Schedule shows how the tutorials, short labs, and assignments relate to your study of the texts.


6.2 Unit 1 (Analogue Principles) Study Guide

This unit is scheduled to occupy about 11 weeks of your study time.

In this unit, the main text, the home computing, and the short laboratories are closely interrelated. Since the short labs will be held at fixed times, you are strongly advised to keep to the suggested schedule as closely as you can.

The first part of the unit develops the basic ideas necessary for the analysis of a.c. circuits and then uses these tools to analyse some simple circuits. Part 2 deals with frequency response and Bode plots while Part 3 examines the a.c. behaviour of feedback amplifiers.

Assignment 01 is associated with Unit 1.

The order of study and the approximate study time for each part of Unit 1 is shown below.

Component Approximate study time
Part 1, Sections 1 to 7 19 hours (incl. Short Lab 1)
Home computing exercises 1 to 2 4 hours
Part 1, Sections 8 to 13 30 hours (incl. Short Lab 2)
Home computing exercises 6 to 8 4 hours
Part 2, Sections 1 to 3 7 hours
Home computing exercise 9 1 hour
Part 2, Sections 4 and 5 9 hours (incl. Short Lab 3)
Home computing exercises 10 to 13 4 hours
Part 3, Sections 1 to 4 16 hours (incl. Short Lab 4)
Home computing exercises 14 to 16 4 hours
Part 3, Section 5 7 hours (incl. Short Lab 5)


6.3 Unit 2 (Transistors and basic circuits) Study Guide

This unit is scheduled to occupy about 7 weeks of your study time. Most of the students find this unit difficult and need a longer time to study it.

This unit is about diodes and transistors: how they work and how they can be used in basic transistor circuits. There are three parts in total in the unit but we only cover Part 1 (p-n junctions and transistors) and Part 2 (Analogue transistor circuits) in ELEC S225. Part 3 (Digital transistor circuits) will be covered in the course ELEC S222 Electronics Principles and Digital Design.

If you have taken ELEC S222, you can just review Part 1 and focus your study on Part 2.

Part 1 (p-n junctions and transistors) is about how the devices work. It goes more deeply into the operation of devices than simply describing their properties, but it only provides enough explanation to enable you to cope sensibly with simple circuits. It does not, for example, give sufficient explanation to enable you to construct transistors or even fully understand how they are made. The explanations given are intended, for example, to enable you to calculate what changes in device characteristics to expect when you change the operating current or supply voltage of a device, or to enable you to look for causes of unsatisfactory performance in circuits that you have built.

Part 2 (Analogue transistor circuits) is about the small-signal performance of several basic transistor circuits, and you will be required to make circuit calculations yourself, and to use OrCAD to perform the calculations for you. You are not required to use OrCAD until after you have read up to and including Section 2 of Part 2 of the unit. You will probably find it more rewarding to read the whole of Unit 2 before tackling the home computing exercises.

The assessment of Unit 2 is covered by Assignment 02.

The order of study and the approximate study time for each part of the unit is shown below.

Component Approximate study time
Part 1 24 hours
(7 hours if you have taken ELEC S222)
Part 2 24 hours
Home computing 11 hours
Supplementary Readings 7 hours


6.4 Unit 3 (Audio Amplifier Design) Study Guide

This unit is scheduled to occupy about 7 weeks of your study time.

The overall aim of this unit is to take you through the design of a 'hi-fi' amplifier. In this process, you will have to recall much of what you have learned of circuit analysis, feedback, and transistor circuits. However, even this is not quite enough, and the unit takes some topics a little further for you to understand fully all aspects of the design. In order not to interrupt the design procedure, the extra background materials have been put in Parts 1 and 2 of the unit, and the amplifier design in Parts 3, 4, and 5. Another reason for doing this is to avoid 'burying' important topics within the design study. In separate sections, they are easier to refer to later.

One way to study this unit is to work straight through from Part 1 to Part 5, studying the more theoretical background materials first. Alternatively, you may find that reading the design in Parts 3, 4, and 5 first helps the study of the background materials. If you wish to study the unit in this way, you should first skim through Parts 1 and 2, then study Parts 3, 4, and 5 in detail. At various stages in the design process, you may have to go back to Part 1 or Part 2 for essential detail, but, for some people, this is an effective way to learn.

The unit contains both short labs and home computing exercises. The text refers to these activities as alternatives, however, you are required to perform both of these components of the course. The assignments set on this unit will assume that you have done the home computing exercises and attended the relevant short labs.

In the short labs, you will be expected to build and test the circuits of the pick-up pre-amplifier of Part 4 and the main amplifier of Part 5. The home computing exercises require you to use OrCAD to check the frequency response of the pre-amplifier design at a few spot frequencies and to use a transient response and frequency spectrum methods to investigate the distortion in the main amplifier.

Assignment 02 is associated with this unit.

The approximate study time for each part of the unit, assuming that the parts are studied in numerical order, is shown below.

Component Approximate study time
Part 1 10 hours
Part 2 12 hours
Part 3 4 hours
Part 4 6 hours
Part 5 11 hours
Home computing exercises 9 hours
Short lab 6 5 hours


6.5 Unit 4 (Power Supplies) Study Guide

This unit is scheduled to occupy about 2 weeks of your study time.

Unit 4 is about how to derive a stable d.c. voltage source of a few volts from the 200 V to 220 V a.c. mains supply. The text concentrates on the basic elements of most types of regulated d.c. supplies using which (a) the a.c. mains can be reduced in voltage to the required level, (b) can be rectified so that the voltage no longer alternates, (c) can be smoothed so that the constant d.c. voltage produced has little mains-frequency fluctuation superimposed on it, (d) the d.c. output voltage can nevertheless be adjusted, (e) the output can be given a low internal resistance so that the d.c. voltage does not change much when the current drawn from it varies, but (f) the circuit is protected against excessive current demands, from short circuits for example, which might otherwise damage the circuit. Such regulated d.c. supplies form a part of all electronic equipment (except those that are designed to be powered only by batteries) and are therefore of considerable practical importance.

There are no short labs associated with this unit, although you will be using OrCAD again to simulate some of the circuit functions explained in the home computing book. The purpose of these simulations is mainly to help you understand the way some of the circuit components operate, rather than to calculate the circuit performance of the completely regulated d.c. supply. There is however no computer handbook for this unit; the computer activities are now incorporated in the main text since it is expected you no longer need detailed instructions on the use of OrCAD.

The assessment of Unit 4 is covered by part of  Assignment 04.

You are expected to spend about 18 hours studying this unit, including about 4 hours of home computing.


Study note

This unit has been written assuming a mains supply of 240 V, 50 Hz. which is the U.K. supply. Here in Hong Kong, the supply is nominally 220 V (but can be as low as 200 V in places) at 50 Hz. The only difference this makes to the discussion is that, for Hong Kong, the calculated transformer turns ratio would be slightly different. When you read Section 2.1, you should calculate the transformer turns ratio required for a supply voltage of (a) 200 V and (b) 220 V.


6.6 Unit 5 (Higher Frequency Circuits) Study Guide

This unit is scheduled to occupy about 3 weeks of your study time.

Unit 5 introduces some of the problems that occur when higher frequency signals are handled by electronic circuits. Such circuits include those in radio and TV sets as well as those in high-speed computers and other digital circuits.

Part 1 of the unit explains how to represent the high-frequency small-signal performance of a bipolar transistor using a high-frequency equivalent circuit, called the 'hybrid-p equivalent circuit'. This circuit is no more than an extension of the low-frequency small-signal equivalent circuit introduced in Unit 2; the main additional elements in the equivalent circuit being representations of the capacitive behaviour of the two p-n junctions of the transistor.

Part 2 is concerned with the problems of making interconnections between electronic circuits, or between circuit components within electronic circuits, which are designed to handle high-frequency signals or high-speed voltage transients. As you will see, the phase changes or time delays introduced by capacitances and/or inductances, associated even with straight pieces of wire, can create problems that need special attention.

Part 2 Required study sections: 1 Introduction, 2 Interference methods, 3 Interference pick-up, 4 Transmission lines
Part 2 Optional study sections: 5 Connections to oscilloscopes, 6 Interconnecting test gear, 7 Digital circuits and lines, 8 Printed-circuit boards

There are no short labs associated with this unit, although you will be using OrCAD again to simulate some of the circuit functions explained in the home computing book. Here the purpose of the simulations is two-fold; they aim not only to help you understand the way transistors and other components operate at high frequencies, but also to enable you to use the computer to calculate high-frequency circuit performance more accurately than can be done using approximate calculations. Again there is no computer handbook for this unit; the computer activities are incorporated in the main text.

The assessment of this unit is covered by part of Assignment 04.

The approximate study time for each part of the unit is as follows:

Component Approximate study time
Part 1 21 hours
(incl. 4 hours home computing)
Part 2 (Required: 1-4) 9 hours


6.7 Unit 6 (Radio Frequency Techniques) Study Guide

This unit is scheduled to occupy about 3 weeks of your study time.

Unit 6 introduces you to some basic radio principles and applications. Part 1 of the unit begins with the basic principles of transmitting and receiving information by radio waves using amplitude modulation and detection. It continues with a description of receiving aerials, and domestic aerial distribution systems. After studying Part 1, you will be required to build and test a miniature radio transmitter in a short laboratory session.

Part 1 Required study sections: 1 Introduction, 2 Basic features of radio communication circuits and systems, 3 Modulation, 4 Radio wave propagation techniques
Part 1 Optional study sections: 5 Aerials and antennas, 6 Antenna arrays, 7 Aerial distribution systems, 8 Amplified aerial distribution systems

Part 2 is devoted to radio receivers. The first half of the text explains basic principles and the design of individual amplifiers. The latter half is devoted to showing how these basic principles are applied to the radio receivers in your home. Finally, in the last short lab session of the course, you will be required to build and test a small radio receiver.

Part 2 Required study sections: 1 Introduction, 2 The radio frequency section, 3 Demodulation section, 4 Post-modulation section, 5 Types of receivers, 6 Details of superhet receivers
Part 2 Optional study sections: 7 A typical domestic superhet receiver, 8 Double superhet receivers

The assessment of this unit is covered by part of Assignment 04.

The approximate study time for each part of the unit is as follows:

Component Approximate study time
Part 1 (Required: 1–4)
plus short lab 7
 14 hours
Part 2 (Required: 1–6) 22 hours

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