Transmission
Transmission is the act of transporting information from one location to another via a signal. The signal may be analog or digital, and may travel in different media.
Transmission: Communication of data by propagation and processing of signals. Signal processing is the representation, transformation and manipulation of signals plus the information they contain.
Signal Types
Signals: An electric or electromagnetic representations of data by which data is propagated (transmitted). All signals are either analog or digital.
An analog signal: is one in which information appears as a continuous variation of some property. Human speech is an example: it produces a continuous variation of air pressure.
Examples of media: Copper wire media, (twisted pair and coaxial cable), fiber optic cable and atmosphere or space propagation. Analogue signals represent some physical quantity and they are a ‘MODEL’ of the real quantity and can propagate analogue and digital data.
A digital signal: is one in which information appears as a sequence of binary values 0 and 1.
Digital signals have two amplitude levels called nodes. The value of which are specified as one of two possibilities such as 1 or 0, HIGH or LOW, TRUE or FALSE and so on. Digital signals can propagate analogue and digital data
To represent these two values, a signal is used in which only two wave shapes are allowed, one representing the binary value 0 and the other representing the binary value 1.
By definition, therefore, a digital signal is a restricted form of an analog signal. A human speaker who only utters the two words zero and one is a crude example of a digital signal.
The difference between digital signals and analog signals:
1. Analog signal is a continuously varying signal while digital signal has discrete values
2. Analog signal has many issues of intensity over a period of time while a digital signal has only a limited number of defined values.
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