Chapter2 framework-for-design

Elec3017:
Electrical Engineering Design
Chapter 2: A Framework for Design
A/Prof D. S. Taubman
September 18, 2006

1 Purpose of this Chapter
It is easy for design texts (and design courses) to begin to read like anthologies of
good ideas. One reason for this is that there are many good ideas and practices.
Another reason is that unless you are actually practicing design, it is hard to
see the relevance of all the suggestions. A third reason lies in the way many
design texts are created, which usually involves numerous industrial field trips
to collect design case studies and sample current best practice.
What is needed is a good framework for understanding design. The most
common framework found in textbooks revolves around the design phases intro-
duced in Chapter 1. Variations on these design phases may be found in different
disciplines of engineering, but there is also a great deal of commonality. The
design phases represent a useful framework, but they are not sufficient. If all
you needed for effective product design was to know the design phases, most of
your university studies would be irrelevant. The purpose of this chapter is to
provide a broader framework for you to understand design. The phases form
one aspect of this broader framework. Hopefully, this framework will also help
you to put your past and future university studies into perspective.

2 Elements of the Framework
The key observation which lies behind the design framework provided here is
that many important design tools and skills are not specific to individual de-
sign phases. It is helpful, therefore, to categorize the various aspects of design
learning into the following five areas:

• design phases;
• design tools;
• technical knowledge;

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°Taubman, 2006 ELEC3017: Framework for Design Page 2

Customer needs solution to a problem Needs assessment

What features/performance are required? Requirements analysis

What is the design problem? Problem statement

What approaches could we take? Concept generation

Block diagram System design

Technical specifications Specifications analysis

Components, circuits, code, etc. Detailed design

Does the design meet the requirements? Prototyping and testing

Figure 1: Typical phases in the design process..

• design business strategy; and
• technical communications.

2.1 Design Phases
We consider only the following phases, although others can potentially be iden-
tiﬁed. These phases are also depicted in Figure 1.

1. Needs assessment
2. Requirements analysis
3. Problem statement
4. Concept generation
5. Concept selection and system design
6. Speciﬁcations analysis
7. Detailed design
8. Prototyping
9. Testing

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The first two phases are most strongly focused on the customer. The pur-
pose of a needs assessment is to identify customer needs which are not met by
existing products, while the purpose of requirements analysis is to determine the
features which target consumers require from products which they need. To help
clarify the distinction between needs assessment and requirements analysis, it
is simplest to take the perspective of a consumer products manufacturing firm.
In this case, needs assessment is an ongoing activity, which seeks to identify
products for which there may be a market. Requirements analysis, however, is
not a general ongoing activity; it is concerned with a specific product concept.
The distinction between needs assessment and requirements analysis is less
clear for consulting engineering firms. In this case, the design process is normally
initialized by a client who already has an identified need. In this setting, the
term needs assessment is sometimes used to describe a preliminary attempt to
document what the client actually wants to achieve. Since both of these phases
are strongly focused on customer perceptions, it is not surprising to find that
marketing is the most important tool which supports them. As noted in the
next sub-section, however, marketing is also important to other phases in the
design process.
The third and fourth phases embody the most conceptual aspects of design.
Problem statement is the process of concisely stating the design problem, with a
view to capturing its most fundamental objectives, challenges and constraints.
Problem statement is more difficult than you might imagine. A good problem
statement should stay clear of two opposing evils. The first evil is that of impos-
ing pre-conceived solution strategies on the problem. Consider, for example, the
problem of designing a new building product for driving nails. It is tempting to
describe the problem as that of designing a “more effective hammer.” However,
this subtly imposes the form of an existing nail-driving solution (the hammer)
on the design process. The second evil is that of providing a problem statement
which is so vague that it is of no assistance in the subsequent concept generation
phase. A good problem statement should be sufficiently specific that it exposes
fundamental challenges and constraints of the design problem. We shall discuss
methods for developing useful yet open problem statements in Chapter 4.
The other primarily conceptual design phase is concept generation. The
main objective of this phase is to generate a large range of potential approaches
to the design problem, at a high level. This requires lateral thinking, as well as
an awareness of relevant technologies. The central distinction between concept
generation and subsequent design phases is breadth. During concept generation,
you aim to find a large set of potential concepts without exploring them in any
significant detail. During this process, it is possible (even desirable) that a
good portion of the proposed concepts have no chance of actually working. A
deliberate lack of depth and willingness to suggest wacky concepts both facilitate
creative exploration of the possibilities. We shall discuss methods to stimulate
the creative process of concept generation in Chapter 4.
System design, specifications analysis and detailed design are the most tech-
nical design phases. These are the central competencies required for a successful
design. All the creative concept generation and problem understanding in the

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world are worthless if you cannot actually generate a design which will work.
By contrast, if you have mastered the technical aspects of design, you may well
be able to find a solution of sorts, even if you have only a narrow view of the
problem with an incomplete understanding of the requirements. This point is
frequently understated by design texts, which tend to focus on the conceptual
aspects of design.
At its simplest, system design is a disciplined approach to the creation of
block diagrams, so as to expose major sub-systems and the relationship between
them. One goal of system design is to provide early identification of critical sub-
systems, whose design might prove challenging or even impossible. This may
force a return to the concept generation phase or even the requirements. System
design cannot proceed until one of the concepts generated in the previous phase
has been selected. It is convenient to lump concept selection and system design
together, since they are tightly connected. For example, rough system designs
for several different concepts may need to be created before a “final” concept
selection can take place1 . We shall have more to say on system design, and
block diagrams in particular, in Chapter 4.
The distinction between requirements analysis and the more technical phase
of specifications analysis has already been elaborated in Chapter 1. Exactly
where the specifications analysis phase belongs in the design process can vary
with the nature of the design problem. Some specifications can be derived from
requirements alone. In other cases, specifications are inherently dependent on
the selected design concept. This often happens in very complex designs. Even
in the simple case of a household electric heater, specification of the heating
element’s power rating may be strongly dependent on selected concepts such as
radiative vs. convective heat transfer.
The one thing we can say is that an attempt to derive technical specifications
should be made prior to the detailed design phase. Detailed design is concerned
with such matters as circuit design, component selection, digital logic design,
operating frequency selection, software coding, algorithm parameter selection,
PCB layout, and much more. There is not much to be said about the detailed
design phase itself, but there is a lot to be said about detail design tools, relevant
technical knowledge and so forth. As such, chapters 6 to 9 are all highly relevant
to the detailed design phase.
The final two design phases, prototyping and testing, are closely connected.
Prototyping plays a particularly important role in Electrical Engineering for two
reasons:

• Massive advances in miniaturization mean that the systems designed by
Electrical Engineers tend to be highly complex, with internal interactions
which are hard to fully comprehend or adequately simulate.
• Low cost and the availability of highly advanced prototyping tools make it
possible to prototype your ideas much more quickly and realistically than
in many other branches of Engineering.
1 Actually, nothing is very “final” about most design activities.

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Accordingly, you should not be surprised to learn that electronic product design
often involves a large number of prototyping phases. In this course, you will
construct a functional prototype of your product. Prior to that point, you may
prototype a variety of critical sub-systems and sub-circuits to better understand
their behavior and interaction. The functional prototype itself, however, exists
only to verify a subset of the final product’s features. Near the end of a product
design process, one or more manufacturing prototypes are typically created to
test as many aspects of the final product as possible prior to manufacture. You
should be prepared to spend more than half of the overall effort of
your design project in the detailed design and prototyping phases.
Testing is, of course, closely connected to prototyping. There is currently a
growing need for capable test engineers in the workforce. One aspect of testing
is the development of test plans, based on the specifications. Testing also goes
hand in hand with debugging. Debugging is the domain of the engineering
“super-sleuth,” tracking problems to their source through a trail of obscure
clues. The need for debugging is unavoidable in complex products. In some
cases, testing and debugging may take as long or even longer than the detailed
design phase.

2.2 Design Tools
We identify the following design tools here, noting that this list is far from
exhaustive.

1. Marketing tools
These include focus groups, surveys, lead user interviews, market research,
monitoring of competitors and other methods to assess consumer needs,
consumer requirements and valuable features for products.
Marketing tools are central to the first two design phases: needs assess-
ment and requirements analysis. However, marketing tools can play an
important role in other phases of the design process. Marketing tools are
used to understand the relationship between features, price and sales vol-
ume, which in turn informs the detailed design phase. Marketing tools
are used to assess prototypes, compare various industrial designs (i.e., the
look and feel of the product), and so forth.
Marketing tools are the subject of Chapter 3.
2. Project management tools
Project management is the discipline you need to carry any complex de-
sign process to successful completion, within budget and time constraints.
Surprisingly, the tools of project management play an important role even
in small group design projects such as that undertaken in this course. At
the end of the course, students are frequently able to point to project
management failures as their chief downfall. Project management is the
subject of Chapter 5.

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3. Economic analysis tools
We look at manufacturing costs in Chapter 11. In the same chapter, we
also introduce tools for economic decision making. These tools help you
to make design decisions on a profit and loss basis.
4. Process tools
We look at quality assurance processes for design in Chapter 14. These are
processes which are used to monitor and continuously improve the overall
design methodology followed within an engineering firm. These processes
are particularly important to the Computing and Electrical Engineering
professions. This is because these professions design systems of such com-
plexity that quality cannot be reliably assessed through testing of the final
product.
5. System engineering tools
Systems engineering is a large topic and an area of high demand for pro-
fessional engineers. A practicing systems engineer has been invited to
provide you with an introduction to this field.
6. Simulation tools
Examples include Spice, Simulink, Matlab, EM finite element analysis
tools, etc.
7. Prototyping tools and methods
Electronic prototyping tools include circuit assembly systems such as
breadboards, veroboard and wire-wrap systems. During this course, you
should learn good wiring and component placement techniques, if you are
not already familiar with them.
Field Programmable Gate Arrays (FPGA’s) provide excellent platforms
for rapidly and convincingly prototyping complex digital designs. Prior to
the development of a custom ASIC, design engineers usually develop an
FPGA implementation. Of course, FPGA’s are also widely deployed in
final products sold to consumers.
Modern micro-controllers come with excellent tool support for rapid pro-
totyping and testing.
8. Computer Automated Design (CAD) tools
In this course, you will use the Atrium (formerly Protel) suite of schematic
capture and printed circuit board (PCB) design tools. We look at PCB
design in Chapter 13.
9. Mechanical drawing
Material in this area is taught separately by the School of Mechanical and
Manufacturing Engineering.

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2.3 Technical Knowledge
In addition to tools, the design engineer needs to be equipped with a wide range
of technical knowledge. This is one of the main reasons you go to University.
Here are some significant areas of technical knowledge, important for design.

1. Electronic components
You need to be aware of the electrical properties, tolerances and ratings
of common electronic components (see Chapter 6).
2. Circuits
You need to be familiar with analog and digital circuit analysis and syn-
thesis techniques.
You need to be able to recognize common circuit configurations.
You need to be aware of the existence of circuit solutions to a variety of
common sub-problems. The more you know, the more likely you are to
be able to come up with good designs.
Circuit knowledge and practice will help make you proficient in reading
and exploiting the wealth of information provided in manufacturers’ data
sheets.
Electronic circuit knowledge is principally acquired through other courses
in your degree program, but Chapter 7 of your lecture notes for this course
provides some useful ideas.
3. Electromagnetic Compatibility (EMC)
This is an area of knowledge to which some effort will be devoted in this
course (Chapter 8). Most people have experienced the effects of electronic
interference through their televisions, radios, mobile phones and the like.
Common sources of such interference include electric appliances (particu-
larly those with commutated motors) and computers.
Designers generally need to be aware of the various modes through which
interfering signals may be coupled. Designers also need to be equipped
with at least some techniques to minimize the effects of interference. In
some cases, designers may need to be familiar with relevant regulatory
standards governing acceptable levels of generated electromagnetic inter-
ference.
4. Feedback and Control
This is one of the fundamental disciplines of Electrical Engineering, and
one which is guaranteed to have enduring value and applicability to a wide
range of problems in design and elsewhere.
The vast majority of analog circuits rely heavily on feedback to provide
predictable behaviour. Feedback is also found in numerous complex sys-
tems, involving analog and digital electronics, software components, and

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so forth. Fundamental questions relating to stability, settling time and
sensitivity to noise can be answered using analytical methods. Moreover,
designers are able to recognize the factors which affect these issues and so
optimize design performance.
Control theory and practice cannot be taught in ELEC3017, for obvious
reasons. Whole subjects in your degree program are devoted to this body
of knowledge.
5. Signal Processing
Many of the project topics or design concepts students first think of in
ELEC3017 require signal processing techniques. Examples include tone
decoding, signal extraction from noise, echo location, voice recognition
and many others. Some of these projects require too much knowledge
or too much development effort to be undertaken in the present course,
but the message is clear: signal processing is a core electrical engineering
which is central to many design problems.
Signal processing theory and practice cannot be taught in ELEC3017, for
obvious reasons. Whole courses in your degree program are concerned
with this body of knowledge. The advanced signal processing techniques
used in many practical designs cannot be taught until the 4th year, in
ELEC4042, due to the intellectual maturity required to appreciate them.
6. Physical Communications
Analog and digital communication techniques, signal recovery in the pres-
ence of noise and interference, error correction techniques, channel equal-
ization strategies and so forth, are all highly relevant to the design of
products which communicate. Communication is not just what happens
when you use your mobile phone. Internal communications within many
complex systems employ sophisticated techniques. In the future, this is
likely to apply even to the communication between sub-systems on a single
chip. Like control and signal processing, communication theory is one of
the fundamental disciplines of Electrical Engineering which is guaranteed
to have enduring value and applicability.
Physical communication theory and practice cannot be taught in
ELEC3017, for obvious reasons. Whole courses in your degree program
are concerned with this body of knowledge.
7. Software Programming Languages
It is important not to draw too big a distinction between software and
hardware. Most electronic products with any level of sophistication in-
volve a combination of both hardware and software components. Electrical
engineering design almost inevitably involves software, and most electrical
engineers spend at least some of their time programming. Control, signal
processing or communication algorithms designed by electrical engineers
are implemented first in software, both for verification and often also for

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consumer deployment. Over time, increasing portions of the design might
be ported to dedicated hardware, first to FPGA’s and then maybe to an
ASIC, so as to drive down manufacturing costs, increase speed and/or
decrease power consumption. One rule of thumb is that moving a com-
putationally expensive process from a general purpose CPU or DSP to an
FPGA will bring a 50-fold increase in speed for a given cost (equivalently,
a 50-fold reduction in cost for a given speed). Moving from FPGA to
ASIC may bring a further 50-fold gain. The corresponding development
effort, however, may be enormous.
Complex designs realized through FPGA’s, ASIC’s, or a combination of
both, normally include embedded CPU’s which must be programmed. At
the other end of the scale, microcontrollers are stand-alone processors
which are designed to realize complete systems with as few components as
possible, by including common I/O hardware on the same chip. Whether
the processor is embedded in a piece of hardware, a microcontroller, or
the general purpose CPU in a desktop PC, programming is an essential
skill for the designer of electronic products.
Programming cannot be taught in ELEC3017, but you should endeav-
our to acquire as much confidence as possible in computer programming.
The Electrical and Telecommunications Engineering syllabi include only
two formal programming courses, but you should endeavour to augment
these skills by taking programming assignments and laboratory exercises
in other courses very seriously. You should also approach programming
aspects of any 4th year thesis project that you undertake as an opportunity
to broaden your skills and increase your confidence/
8. Hardware Description Languages
Digital hardware design itself is too complex to be done entirely man-
ually. Instead, hardware designers must learn to program in hardware
description languages such as Verilog or VHDL.
Hardware description languages cannot be taught in ELEC3017, but you
should consider acquiring this valuable skill to round out your capabilities
as a design engineer.
9. Manufacturing Processes
Successful design cannot be carried out in isolation, without an awareness
of the manufacturing processes that will be used to manufacture the de-
signed product. The sequential approach of first designing a product and
then handing it on to manufacturing engineers to “tweak things” for ease
of manufacturing has been abandoned long ago. The sequential approach
takes too long, costs to much, and may produce designs which simply can-
not be manufactured. Concurrent engineering is the term used to describe
the integration of manufacturing considerations during product design. In
this course, you will be introduced to some of the relevant manufacturing

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considerations (see Chapter 12). You will also be required to incorporate
manufacturing considerations into your design project’s final report.
10. Safe and Ethical Design Practices
Safety is a strong focus of modern product design, and rightly so. De-
signing for safety is the subject of Chapter 9. Broader ethical issues in
electrical engineering are the subject of an entire course in the 4th year of
your program and a condition of accreditation by the Australian Institute
of Engineers.

2.4 Design Business Strategy
1. Regulatory and industry standards
Some standards are the subject of government regulation so that being
aware of their existence and following their stipulation becomes a matter
of law. The majority of standards are created by industry representatives,
usually in open fora, but sometimes in closed consortia. These standards
govern the way in which products should be designed so as to success-
fully interoperate with each other. Customers should be unwilling to buy
products which cannot interoperate with related products from other man-
ufacturers. Since these standards are created by industry representatives,
there are strong business incentives to participate in standardization ac-
tivities. We shall have more to say about this in Chapter 15.
2. Intellectual property
Intellectual property is the term used to refer to patents, copyright, trade-
marks and some less well-known forms of legal protection such as regis-
tered designs. Patents are a strong form of legal protection. Patents held
by others can prevent you from designing and marketing products which
incorporate the protected ideas, regardless of whether or not you come up
with the ideas independently. By the same token, maintaining a patent
portfolio of your own can be an important business strategy. You cannot
afford to be ignorant of patents and how they work. Chapter 16 is devoted
to this topic.

2.5 Technical Communication
1. Written communication
Technical writing is a vital skill for design and for your career in general.
General writing ability and language proficiency certainly help, but there
is a lot more to good technical writing. Technical writing also plays an
important role in this course, being the subject of Chapter 10.
2. Oral presentation skills
The ability to prepare and deliver an effective oral presentation is not
something you were born with. This is a slightly less important skill than

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Table 1: Topics taught in ELEC3017
Topic Week Most relevant design phases
Marketing (tools) 2 needs + requirements analysis
Concept generation (phase) 2 concept generation
System design (phase) 3 system design
Project management (tools) 3 all
Electronic components (knowledge) 3-4 detailed design
Circuit ideas (knowledge) 4 detailed design
EM compatibility (EMC) 4-5 detailed design + testing
Prototyping methods (tools) 5 prototyping
Specifications and testing (phases) 5 specifications analysis + testing
Safe design (knowledge) 6 detailed design
Technical writing (communication) 6 all
Costing and economics (tools) 6 detailed design
Quality assurance (tools) 7 all
Standards (strategy) 7 detailed design + testing
Intellectual property (strategy) 7 concept generation + system design
Manufacturing (knowledge) 8 system design + detailed design
Systems engineering (tools) 8 detailed design
PCB design (tools) 9 detailed design
Mechanical drawing (tools) 10-11 detailed design
Oral presentations (communication) 12-13 all

technical writing, but still deserves some significant attention. Confidence
in your own understanding of the design problem and your design solution
are key ingredients to success in the ELEC3017 project seminar.

3 The Framework Related to ELEC3017
For a variety of reasons, teaching in ELEC3017 will not be organized solely
on the basis of the categories presented in the previous section. One of these
reasons is that you need to receive information in an order which best facilitates
your ongoing design project. In the end, the categories are most useful in
helping you to see how the things which you learn fit together. Quite a bit of
this course focuses on design tools and knowledge, rather than specific design
phases, but the framework allows you to see how these tools relate to one or more
of the design phases. Other aspects of the course exist to extend your technical
knowledge. In this respect, though, the course serves only to supplement your
learning in other courses, all of which are ultimately intended to help you design.
Table 1 provides a convenient summary of relationship between topics taught
in ELEC3017 and the design phases to which they are most relevant. As for
your formal written lecture notes, the topics covered should be as follows2 .
2 We say “should be” because these lecture notes are still being written.

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Chapter 1: Introduction to Design
Chapter 2: A Framework for Design
Chapter 3: Tools — Marketing
Chapter 4: Phases — Problem Statement, Concept Generation and System
Design
Chapter 5: Tools — Project Management
Chapter 6: Knowledge — Electronic Components
Chapter 7: Knowledge — Electronic Circuits
Chapter 8: Knowledge — Electromagnetic Compatibility
Chapter 9: Knowledge — Safe Design Practices
Chapter 10: Technical Writing
Chapter 11: Tools — Economics and Costing Design
Chapter 12: Knowledge — Manufacturing Processes
Chapter 13: Tools — PCB Design
Chapter 14: Tools — Quality Assurance
Chapter 15: Strategy — Standards
Chapter 16: Strategy — Intellectual Property

Chapter2 framework-for-design

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