THE CONCEPT OF MODERN COMMUNICATION SYSTEM ARCHITECTURE
INTRODUCTION
The electronic transmission of
information over distances called telecommunications has become virtually
inseparable from computers. Computers and telecommunications create value
together.
Telecommunications are the means of
electronic transmission of information over distances. The information maybe in
the form of voice telephone, calls, data, text, images or video. Today,
telecommunications are used to organize more or less remote computers systems
into telecommunications networks. From the very beginning man has constantly
searched for means of passing information beyond the normal range of human
vision and hearing. Everyone is familiar with such methods as Indian smoke
signals, beacon fires, and semaphore flag signaling. It is worth pointing out
here that “Tele” is derived from an Ancient Greek for “at a distance” “phone”
means sound or speech “graph” means writing or drawing. A telecommunications
network includes the following components:
·
Terminates
for accessing the networks
·
Computers
that process information and are inter connected by the networks
·
Telecommunication
links that form a channel through which information is transmitted from a
sending device to a receiving device.
·
Telecommunication
equipment that facilitates the transmission of information.
·
Telecommunication
software that controls message transmission over the network.
A system architecture or system
architecture is the conceptual model that defines the structure behaviour and
view of the system. An architecture description is a formal description and
representation of a system organized in a way that support reasoning about the
structure or the system.
A system architecture can comprise
system components, the externally visible properties of those components, the
relationship (e.g. the behaviour) between them. It can provide a plan from
which product can be procured and system developed that will work together to
implement the overall system.
There is no universal agreed definitions
of what aspect constitutes a system are lecture and different organization defines
it in different ways including:
·
The
fundamental organization of a system, embodied in its components, their
relationship to each other and to the environment and the principles governing
design and evolution.
·
A
representation of a system including a mapping of functionality on to hardware
and software component, a mapping of the software architecture and human
interaction with these components.
·
A
description of the design and content of a computer system. If documented, it
may be includes information such as a detailed inventory of current hardware,
software and networking capabilities: a description of long range plans and
priorities for future purchases and a plan for upgrading / or replacing dated
equipment and software.
·
A
formal description of a system or detail plan of the system at component level
to guide its implementation.
Based on the overview above, a system
architecture can be said to be a set of representations of an existing (or
future) system. It conveys the informational content of the element comprising
a system, the relationship among those elements and rules governing those
relationship of which may consists of hardware, software, documentation,
facilities, manual procedure or roles played.
A system architecture primarily
concentrate on the internal interface among the system component or sub system
and on the interface between the system and its external environment especially
the user.
One can contrast the system
architecture with the system architecture engineering (SAE) the method and
discipline for effectively implementing the architecture of a system.
Brief history
It is important to keep in mind that
the modern system architecture did not appear out of no where. Systems
architecture depends heavily on practices and techniques which were developed
over thousand of year in many fields, and perhaps the most important being civil architecture.
Prior to the advent of digital
computers, the electronics and other engineering discipline used the term
“system” a it is commonly used today.
However, with the arrival of digital
computers and development of software engineering as a separate discipline, it
becomes imperative to often necessary to distinguish among engineered hardware
artifact, software artifact and the combined artifacts.
By analyzing, a system architecture
make use of element of both software and hardware and is used to enable design
of such a composite system. A good architecture may be viewed as partitioning scheme,
or algorithm which portioning all the system present and foreseeable
requirement into a workable set of cleanly boundial sub system with nothing
left over. That is, it is a portioning scheme which is exclusive, inclusive and
exhaustive.
TYPES
Several types of system architectures
principle have been identified as follows:
·
Hardware
architecture
·
Software
architecture
·
Enterprise
·
Collaborative
system architecture (such as the internet, intelligent transportation systems
and joint air defense systems)
·
Manufacturing
system architecture
·
Strategic
system architecture
ANALOG AND DIGITAL COMMUNICATIONS
Most of the lines in the telephone
systems of the world at present are analog. Signals are transmitted as
continuous waves. This is satisfactory way of transmitting or to transmit
voice, but digital data sent by computers (sequences of pulses representing Os
and 1s) must be converted into an analog signal to transmission over an analog
line. The analog data must then be converted back into before entering into the
memory of the recievig computer. The conversion of data from digital form into
analog for transmission and then back into digital at the receiving end is done
by a pair of interface devices called modems (modulator-demodulator).
Modem-based telecommunications have
created a significant bottleneck in an environment where computer and
peripheral speeds have increased dramatically. The solution is end-to end
digital communications, in which signals are sent as streams of on/off pulses.
Digital lines are capable of much faster communication and digital circuitry is
now cheaper than analog. All new equipment now installed in telephone networks
is indeed digital.
MODERN COMMUNICATION SYSTEM
Modern communication systems include:
Satellite, fiber optic, mobile
cellular phone, micro wave systems, internet communications, as well as cable
TV, AM & FM radio, VHF, HDTV, software, fiber, police, telephone, fax,
voice, TV, local government, and computer networking systems.
REFERENCES
Hannu,
J (2011) Architecture-driven modeling methodologies
in proceedings of the 2011 conference on information modeling and knowledge
base.
Paul,
C (1996) A survey of architecture
description languages in proceedings of the 8th international
workshop on software specification and design.
Boris,
G (2008) The Art of system architecture
Muller,
G (2012) Systems architecture business
perspective
Boris,
G (2002) The fundamental principles of
system architecture
Brad,
D (1998) Choosing a strategic system
architecture
Richard,
N (2002) A classification and
architecture description and engineering.
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