Media Signals/Forms of Data Transmission:
The signals that pass along physical wires and wireless media
can be classified as either analog or digital.
a. Analog Signals:
Analog signals carry data as continuous wave. For instance,
the human voice consists of numerous complex inflection that are combinations of
sound waves. Much of the phone system still in place across the world which was
implemented years ago to capture the richness of the human voice is an example
of an analog transmission medium. Telephones, radios, and televisions the older
form of communications technology were designed to work with analog signals. An
analog signal is a continuous electrical signal in the form of a wave. The wave
is called carrier wave.
Two characteristics of analog carrier waves that can be
altered are frequency and amplitude.
Frequency is number of times a waves repeat during a specific time interval; how many times it completes a cycle in a second.
Amplitude is the height of wave within a given period of time. Amplitude is actually the strength of volume, the loudness, of signal.
b. Digital Signals:
Digital signals carry data as on/off or high/low or
present/absent electrical signals. Thus, the-1bit of a data byte can be
represented as an on (high) signal; the 0-bit, an off (low) signal. The new
equipment being installed by phone companies is designed for digital
transmission of both data and voice.