has since then been widely applied to a large number of varied situations and mainly by
behavioural scientists (cf). The model describes communication as a linear, unidirectional process; there is one lateral contribution from a dysfunctional factor, noise.
. In graphical form it is usually represented as in the diagram below:
communication model
signal should be adapted to the channel leading to the receiver. The function of the
receiver is the opposite of that of the transmitter. The former reconstructs the message from the signal . The received message then reaches its destination. The signal
may be disturbed by noise; this may result in a difference between the transmitted and
received signal. (cf,basicmodels).
Matelaart (cf) in discussing this model notes that researchers in many disciplines(some quite remote to telecommunications) borrowed Shannon's notions of
information,transmission of information,encoding, decoding, redundancy, disturbance and free choice. The conception of the communication process as a straight line bet.
a starting point and a point of arrival was to have a profound influence in the
development of social sciences in the second part of this century.
In an attempt to adapt the
model to a garden situation as that outlined on the previous page we will
adopt first a simpler version of the model. To simplify, we assume that the transmitter
is included inside the information source, so that the message comes out of the source
already as a signal. Also, in the receiving end, we include the receiver into the destination. In other words, the received signal is turned into a received message inside
the destination. A further change has been to enclose both the information and the noise source inside a box; this in order to illustrate the notion that the noise type we
considering is internal noise (explained further on). This simplified model is illustrated in
Diagram 4 below:
Signal
Information
source
Destination
source
signal and noise are "mixed". From there on they proceed towards the destination as
a single complex signal to be received.
Noise is very often defined in telecommunication as " any unwanted signal that interferes with the proper transmission of the message" . In a more general context, Noise is defined as :
"any unwanted signal tending to interfere with the normal operation of the system " . The noise source can be external (atmospheric noise,solar noise etc) or
internal (thermal noise, shot noise,etc). In our model we ignore external noise and
assume all the noise to be internal so that both signal and noise are produced in the
same region of space(the square box).. System optimization will require that the
message produced by the infosource be as similar as possible to the message at the
receiving end. Within this context the performance of the system will be a function
of the relative values of the signal power and noise power. The relationship bet.
both is usually expressed as the Signal to Noise Ratio:
S/N or SNR = Signal Power/ Noise Power
The concept of SNR will be extensively used in our adaptation of
Shannon's and Weaver model to gardening.
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Note: I've tried to avoid going into
any detail regarding concepts
of comunication theory. The interested
reader is refered to other Web sites which
treat the subject more in depth.
