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The flexibility of electronic techniques has resulted in their
permeation, in a remarkably short time, of most spheres of human
activity. Research in both the arts and sciences has benefited, services
such as entertainment and communication have been transformed, transport
and defence facilities are highly dependent on electronics, and a
significant and growing role is being played in fields such as medicine,
materials production and administration among many others.
The design of electronic equipment thus takes place in many different
types of organisation and for a great variety of purposes, and this has
to be kept clearly in mind when discussing electronics design. The
outlook of a designer of electronic equipment for general sale differs
considerably from that of one designing for use within his own
organisation. Designing for quantity production is very different from
designing a single working unit. Within one organisation, the approach
of one design group may be quite distinct from that of another covering
a different field of application or based on another electronic
technique. An engineer designing general-purpose electronic equipment
needs quite different attributes and would express quite different views
from one concerned with apparatus for a specific application.
The profusion and divergence of opinion on the design of electronic
equipment resulting from the different objectives and facilities make
the study of basic design processes very difficult. At the same time the
level of electronics design activity is so high and its importance in
such areas as trade, public services and research is so great that an
understanding of these processes and their relationship to the fields of
application and types of design organisation would be very rewarding.
What is design?
One of the most difficult problems is to say precisely what we mean by
'design'. We can get a measure of the task by taking a few statements at
random:
(a) 'Our designers should be concerned with cost as well as appearance.
. . .' -extract from speech by the Duke of Edinburgh, May 1964
(b) 'A multivibrator may be designed as follows . . .'
(c) 'There is really no difference between design and development'
(d) 'The original design came out in 1948, and since then we have
developed it a good deal'
(e) 'When we have developed a working model, we pass it to the drawing
office who carry out the design work'
(f) 'At the conclusion of the design process the final result must be
carefully defined so that it can be built—this is the function of layout
draughtsmen and detail draughtsmen' - extract from 'An outline of the
requirements for a computer-aided design system', by S. A. Coons. |
(g) 'Mechanical engineering
design is the use of scientific principles, technical information and
imagination in the definition of a mechanical structure, machine or
system to perform prespecified functions with maximum economy and
efficiency' - Feilden Report.
Clearly, no single definition will
cover all views on design, and the only reasonable course is to
formulate and promulgate a working definition that reflects the
particular approach to electronics design appropriate to the study,
while recognising the possible validity of other definitions based on
different approaches.
The working definition adopted by
the committee with respect to electronic equipment is as follows:
Design is the process of
establishing relationships between all relevant characteristics of an
equipment.
We can say, quite generally, that
any item of electronic equipment has a set of characteristics such as:
|
cost |
performance |
appearance |
|
size |
reliability |
ease of use |
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weight |
adaptability |
maintainability |
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novelty |
versatility |
developability |
The working definition of design
is based on the view that the essence of designing electronic equipment
is the establishment of relationships between all these characteristics,
taking into account the environment in which the design is undertaken.
The latter includes such factors as the time available for design, the
quantity required and the availability of engineers, materials and
production resources.
Thus the designer integrates or
synthesises all the characteristics, giving different degrees of
emphasis according to the circumstances in which the equipment is being
designed and the use to which it is to be put. If the equipment is being
made for general sale, the appearance, cost and quantity required are
usually of great importance, whereas if an item with the same
performance is being designed for use within an organisation, the
quantity required is usually small, and cost and appearance may be
subordinate to most other characteristics. For a particular research
project, technical performance and the time taken to design and make the
equipment may be the overriding factors, while in another case
reliability and ease of maintenance may be paramount. For a piece of
equipment for use on a production line, reliability and ease of use may
take precedence over cost, size and weight.
These varying degrees of emphasis
and the different environments in which evolution of an equipment takes
place give rise to much of the confusion over the word 'design'. If,
however, we remember the broader picture implicit in the working
definition, we are a good way towards putting the discussion of design
on a rational basis. |